Low libido 22 year old male

I've been very stressed the past few months and during that time my libido has been low to none existant. I've been to my Doctors twice in the past two weeks and they've dismissed it as stress/depression. The problem is I've read low libido can be caused by serious illnesses and that's making my stress worse and I'm finding it impossible to get that thought out of my mind even though my Doctors don't really seem concerned. I keep managing to get it on the way back up but then it falls right back again. For example yesterday I woke up with an erection after having a sexual dream and on Wednesday I actually got aroused without being in bed with my girlfriend.

I can still get erections and in the right situation I'll still get turned on. At the moment I need to be with my girlfriend and us to be kissing, naked, etc for anything to start happening down below. Outside the bedroom I'm finding it difficult. Previously if I saw a woman I found attractive that'd be all it would take for me to get turned on.

I suffered from low libido/erectional problems last year for a couple of months when I was worrying I was infertile which turned out not to be the case. Things went back to normal after that.

I'm booked to see my Doctor again on Monday but could anyone give me advice on this?