A dirty syringe is never something to take lightly, as they can often be infected with aids, or hepatitis. You should have cleaned out the wound, and been tested promptly afterwards. Aids has a low survival rate outside of the body, however there is still a risk with a syringe. Hepatatis on the other hand can live outside of the body for prolonged periods of time (months). Please go to the doctor and tell them your situation. You need to be tested for hiv and hepatitis. I doubt you contracted anything, as you would most likely have symptoms by now, but just to be on the safe side.

I could tell you a story about getting stuck with a needle, but it's a personal one.

Go and get tested for every single condition which could be contracted through blood to blood contact. Don't listen to anyone else! Just go get fully tested.

10 years ago?! You would be dead by now if you had gotten infected with something.