Can large doses of testosterone effect PSA levels?

Yes, but for a variety of possible reasons I can't speculate. You will have to see your Doctor for a digital prostate exam and see what he says about that first. Be honest with him too as if you lie and when your Testosterone levels are abnormally high, you can't hope to get proper treatment. At worst you might get something disastrous prescribed.

As a worst case scenario and it were cancer; currently you would be fueling it's growth at alarming rates where normal Testosterone levels would give years for treatment; really high Testosterone levels might turn that into months before it metastasizes. I think that is something to think about and worth considering.

Cheers.

Good luck with the Doctor