As you did have a risk from a broken condom and the head of your penis showing, getting tested was the right course of action. Now that you have multiple negative tests in the proper time frame to be accurate, you can rest easy as you do not have HIV. In fact, it is less than 2 percent chance of HIV from a single encounter of a broken condom so the risk was very close to nothing. So, do not worry and move on as you do not have HIV from this.
Hello dragonpulse, I tested at 48 days and it was negative too !
If you went for a duo combo ag/ab test, it would be accurate 28 days after the exposure. As you did it 36 days after the exposure, your result is accurate. No need to test again 45 days later.
All the best.