Is this in my head, or should i be concerned?

So, i noticed the problem, now that i have a girlfriend that i cant, litearlly cant cum in any other position than laying down on my back, squeezing the muscles of legs, i dont know if its the problem in my libido, because i also noticed it dropped a bit, but i think the problem is that i started playing with myself when i was younger the way i cum now, so i squezed legs and it was a nice feeling… is there any way i can overcome this? I know it doesnt seems like a big deal, but its bothering me. I researched also about performance anxiety, but when im all by myself i cant end in any other way eaither, thanks for advices