There could be a number of explanations for your symptoms. You need to have a physical exam to rule out possibilities and to put your mind at ease. It's unlikely to be poison unless you know for sure that you consumed something that was poisonous. There are two things you can do for a start. First, to put your mind at ease, call the Poison Center 1-800-222-1222 and tell them your concern and what your symptoms are and ask if those symptoms can be the result of a poison taken sometime earlier in the year. They are very kind and helpful. I've used them when I thought I may have accidentally exposed myself or my children to a substance. Before you call them, make a list of all possible substances you think might be causing your symptoms. But, I would think if you had been poisoned, you would have felt the symptoms much sooner than now.

The other thing you can do is find a free medical clinic in your area to get yourself a physical checkup. The yellow pages in a phone book in your area should have free clinics listed. Doing these two things for yourself will give you control over your situation and calm you down. Some of those symptoms could definitely be caused by anxiety stemming from your fear.

The symptoms you describe could be due to a wide variety of physical or possibly mental medical or somatic disorders rather than poisoning. So I am not clear why you so strongly believe you have been poisoned rather than you having some other illness or medical disorder causing these symptoms?.
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But just assuming you are right in saying you have somehow been poisoned what you seem to be insinuating is it is something very long term that is still inside you (a bit like a Trojan virus) and such a possibility could either be as a result of somebody else putting it in you whether deliberately or accidentally, or else some mistake you yourself made, such as drugs or something else happening to you like an open wound on you not to being looked after properly last year?

Frstly then let us review the various ways poisons might possibly get into your body and whether they could be relevant to your experiences Poisons can be be swallowed by your eating something, such as improperly cooked chicken giving you salmonella infection . Poison can also be inhaled such as breathing in a poisonous gas ? Or as a result of nuclear radiation (gamma rays or neutrons) but have you been near any nuclear power stations or near nuclear test sites or anything like that or in a home where there could be materials that emit radon?

Or poisons can be absorbed through your skin or injected under your kin, such as poisonous venom after being stung by an insect or bitten by a poisonous snake. You need to think back, could any of that have happened to you, perhaps without you even realising it?

To try to narrow possibilities down , considering the symptoms you report, if it really is poisoning as you suggest it seems to be what is termed "chronic poisoning". That means harm that has resulted to you from the gradual accumulation of a poison inside you which did not get eliminated by your body quickly? That does seem to rule out some kinds of poisoning, like it being something you swallowed. Because food poisoning usually results in you being violently sick or getting acute diarrhea whereby your body gets rid of the poison quickly to correct your mistake i.e. the effect of that is short term not chronic? Have you any reason to believe you might have breathed in a poisonous gas?.

But another possibility, poisons can indeed originate within your body and accumulate over a long time period from bacteria in you . Bacteria can produce poisonous endotoxins which are only released into you after the bacteria dies. if that happens that causes a big drop in your blood pressure which can be dangerous, but have you had your blood pressure checked? Or there are Enterotoxins which are released by the bacteria that inflame the lining of your stomach? .

Or another possibility leading to some of these symptoms of chronic poisoning would be Exotoxin. These poisons are also released by certain bacteria (such as tetanus bacilli which originally get into you through a wound in your skin and then when inside you the exotoxin produced your nervous system to cause you to have muscle spasms or paralysis in you and various other effects throughout your body, which does seem closer to the symptoms you describe? . So you really need to think back if you have had a skin wound during past year that could be the culprit?

But also apart from that type of poisoning, there are various disorders such as kidney failure, liver failure and certain metabolic disorders can cause poisonous substances to be produced inside you too, so have you perhaps could you have any of them?

You see there are so many possibilities to consider about poisons. But essentially many of these sorts of poison can only be checked by a blood test, blood pressure check and perhaps x rays none of which do you appear to have had?

So the only suggestion I can really give you is to go back to the doctor and ask to be given a blood test for possible exotoxin poisoning and explain why you think that might be affecting you. Sorry I can not be more helpful but hope that indicates what you need to think about.

Wow, thank you, your responses were quite knowledged and helpful, I appreciate very much... I will heed the advices given:)

Very detailed and alot of insight given.