how do I know i have pied?

So, i know for sure a year ago when i started this i had PIED. I could not get it up. but since then. I have progressed a lot and now thiings are different but i dont know if i have pied. sometimes i can have sex with my girl and my penis is super hard. other times it is not that hard and i feel insecure that fucks me up. and when i relapse and during the next days i want to have sex, i feel less in my penis and i get less hard. maybe it is mentally or idk. recently i went thru a hard period of relapsing and this time when i had sex. i got hard but as soon i stopped thrusting, my penis kinda went soft and also after having sex for more than 10 minutes. my penis goes softer and softer.
someone has tips to make me feel more , oils or products that i can put to my penis in order to make it feel again , to repair the damage .
PS: when i relapse it is without any lubrication. just my hand so idk maybe that makes it worst cause vaginas are slippery and not dry like my hand. any tips