You can find out your status by testing 3 months after your last exposure.
If you abuse IV drugs, you must be vigilant about not sharing any equipment used to inject. Use all of your own supplies. That will ensure that you won't ever be at risk for HIV, or Hep C or B. BTW, you should be testing for Hep B and C if you've shared works as well. You can post in our Hepatitis forums for more info about that.
You'd do yourself a favor and seek help if you are abusing drugs.
Are you a chronic IV drug abuser and what was your exposure?