Injecting cocaine? never heard of that before!
Even if she had HIV, the risk was approximately 1 in 2000. Don't bother with home access, go to hivtest.org and find a testing site near you where it can be done for free by people who know what they're doing. HIV + people have blood taken all the time; the fact that you had problems drawing blood is in no way indicative of your status.
Highly, highly unlikely you were infected:)
As dobber21 already responded (below), you describe a low risk exposure. You can judge better than I can whether your partner is telling the truth about her own health, but most likley she is. Get a grip and put life's risks in perspective: the chance you caught HIV are less than the chance you're going to die in the coming week from some accident or illness. If you're going to worry about HIV in this circumstance, you also need to decide never to drive, to not cross busy streets, and not take commercial flights.
Good luck-- HHH, MD