Desperation mode (Please help)

Hello everyone,

I am a 37-year-old male. I have accomplished 72 days PMO, which is by far the library streak on my life. I can honestly say that porn is way way behind me. Here's a little more background:
1.- I have been dating a girl 2 months ago
2.- I have been experiencing some soft some strong erections just touching her or holding her hand
3.- My morning woods are frequent and strong.

Issue:

I slept with my girlfriend three times this week. The first two times we didn't have sex. The third night we tried and here are the problems.
1.- I was semi hard, but went soft after penetration
2.- I ejaculated almost immediately in a soft penis

Questions:
1.- Since my erections have been improving, can I assume that this incident is mostly due to anxiety and psychological?
2.- Has anyone experienced this? Is this curable?
3.- Should I take pill to help my issue?
4.- Should I go for a longer reboot?

Any help, insight, or guidance you can provide will be appreciated

TIA