Sorry to hear about the anxiety and stress you’ve been experiencing. However, it sounds like you’ve had adequate testing, and you should feel confident in the negative test results that you’ve received.
Sometimes when blood is drawn for an HIV test there is not enough blood collected in the tube and the lab cannot complete the test. That does not mean there was anything concerning about the blood, just that there was not enough blood to run the test. If you want you can re-test with your doctor, but if you’ve had a test done 7 months after sexual risks that test will be accurate.
As far as your girlfriend’s symptoms (the yeast infection) that is a very common thing to happen, and likely doesn’t have anything to do with you. Itching and discharge are very common with yeast infections, and a doctor would be able to distinguish between a yeast infection and an STI (even if your girlfriend didn’t talk about sex with the doctor).
Overall, you should feel good about the tests you’ve had and the results that came back (all negative). It sounds like your girlfriend’s symptoms don’t have anything to do with you (just normal health stuff that happens sometimes).
It is also common for people to worry about STI even though all their STI tests are negative and they were tested outside the window period. I would recommend having a look at our worry page for some helpful information on what to do in these situations.
I hope that answers your questions, please feel free to leave a comment or ask another question.
All the best,