About a year ago I also suffered from low erections & week sex drive.
My problem was purely mental, I thought I had an STD & after numerous testing everything came out clean (negative) but that didn’t help one bit.
I also broke up with a girl I was with at that time (same scenario as yourself, she didn’t give me the chance) so I was pretty depressed & thinking of women & sex made it worse.
After a while I stopped caring & turned to studying for my exams & body building, erections became better but I still didn’t have my usual sex drive back.
Then I met a girl.last time I had sex was 6 months ago & it didn’t went very well so I was afraid my boner would be weak.
Luckily sex was great & now I can’t stop having rock hard boners, I feel like a teenager again with a healthy libido & a wonderful girlfriend.
Also, PE helped so keep at it ;)