I can't bring her to the top

So me (24M) and my gf (22F) have been dating for 3 years now. At the beginning I was so nervous and afraid of not being enough sexually for her and I really wanted to be good in bed when we started our relationship (and still want to be now too). But after 5-6 months I started to last short and cum in like 2-3 minutes even if I hold my breath, stop for a few sec or something. I'm not into porn too much, sometimes watch it like two or three times in a month but that's it. I think I'm the fastest shooter in the world. Sometimes when she give me a head, my penis isn't really hard and I cum instantly.

I'm not experienced in this because my partners before my gf were not experienced too and I had sex like 10 times before her. Now she is always upset, can't think about sex and if I say something spicy both of us start to feel uncomfortable because of this.

She cried once because I cum and it was really fast but I tried to hold it and she did not cum and yeah.. so hard to fight against something I can't understand how it works.

Please give me some advice with this.

Edit: we always start with foreplay and she said it's perfect, sometimes I make her twice with my tongue before penetrate.