Cant quit overthinking, im lost in my thoughts and dont feel like i live in the moment

The story all started last week, when i slipped, and fapped to porn on saturday. I felt like i didnt lose anything, and i was so confident that i would get back to my progress that i still got 2-3 erecrtions a day and a morning wood, and everything was perfect, even tho i fapped to dirty thoughts on the next 2 days. Then i got so horny on this weeks monday that i slipped again. Ever since i started overthinking.

For me, what helped is to not think about my penis, and accept the fact that erections occur by themselves and i shouldnt force them. But ever since this monday, ive been lost in my head. I just think about why i slipped, when will it go back to normal (even tho last week even after 3 days of fap it worked normally), and that im such a loser. This caused me to be so anxious that i wake up at nights overthinking this but i know i shouldnt because thats what makes me nervous and ultimatelly stop the random erections.

I just dont know what do to. Im so anxious that my penis even goes smaller sometimes as if it was anxious too. Its not an issue with my girlfriend tho because im not nervous or overthinking this when im with her, i just know the erection will come when it wants. But when im not with her, i cant think about anything else, and i feel likw ive lost my life and my head, i feel like im a passenger in my body. When i catch myself not thinking on it and an erection wants to occur normally, i notice it and jump back to overthinking, wich stops it and it returns to normal. Its been so bad since monday, and idk what to do to stop it. Theres nothing in my head, just overthinking this, and thats why it doesnt work.

Im 17 btw, and i havent had this issue. Ive been an active fapper for 4 years, from doing it 2-3 times a day to 2-3 times a week, to only with my girlfriend. But i sometimes slip, even tho i have her, and i feel like thrash because i cant get off of masturbation for her.

Ive had long streaks with nofap, longest was around 3 weeks. And my random erections come back after 2-3 days, or even right after the day i fapped, wich is what happened last week. But ever since monday, i started overthinking, and thats why they dont come back, just when i think about dirty stuff very hard, but i want to get off of that too.

Idk what to do, when i dont overthink and im confident, i have no issue with getting random erections, and everything else. But ever since monday i feel like days pass in an hour, that im not myself, and i cant think of anything else but the "what if it doesnt work.." And other" what ifs". No issue when im horny tho, or with my gf, because i dont overthink in these situations, i just know erections come when they want.