Unanswered questions

I'm doing the nofap challenge and haven't PMO in about 2 Months I think. I didnt plan on doing the NoFap challenge, so I dont really know when exactly i startrd.
Quick notes about myself:
I'm 19, male, PE (is it curable?) and some kind of PIED (will get to that later), in good physical health and have a sexual partner.
Since i stopped masturbating I only realized a few changes. One of those things is the PIED. Maybe I'm confusing this with flatline, but basically its kinda hard for me to get hard in some situations. I.e. when my girlfriends send me really hot nudes. Oh my god, back then I would be rock hard but now I'm not reacting to it at all. Another example is when I came in less than a minute and can't get hard for second round because I'm probably ashamed of myself for comming so quickly and not being able to give her what she wants, although she told me she's fine with it but i know she wants that D some longer. What should I do about this?
Another thing I noticed is that I'm not soextremely sexualizing everything. Thats probably the only good thing I got from nofap.

Not masturbating is really not a problem for me since I dont feel an urge to do it but I kinda still want to masturbate to somehow reduce my PE. The last time I had sex after a long pause I came in 15 sec and exploded. I want to stop that by masturbating a day before or so but i also dont want to ruin my progress. I need help on that.
Stop-and-go method doesnt help at all.

I don't really know how far I am in this reboot thing. I tried to find some answers in these forums but couldn't find any. I want to know how much time it would take for me.

And the last question I have is about the Flatline. I obviously am deeply in the flatline and i don't know if this will ever end. Can anyone tell me anything about this?

Thanks a lot!