Erection Problems,

Hey well, tbh, I was a bit scared of posting all this, but its better to just get it over with...

Basicly, sometimes I have problems getting hard,
Sometimes I'll be watching Porn, and I'll end up getting an erection straight away, but sometimes i'll have to watch a bit of a video for a while before I get hard,

Or sometimes I have to struggle to get hard,
Same goes with ejaculating too,
Sometimes it'll be easy, sometimes I'll have to struggle,
Although nearly all the time I end up ejaculating with the thought of my ex, (We broke up in January)

Although if I'm out I ALWAYS look at other Women, at like, there hips/butt/chest...

I tend to suffer with depression half the time and I tend to not get alot of sleep,

But I'm starting college in September and really wanting to find myself a new girlfriend, and to be able to get intimate with her, but I'm worried that I won't be able to get it up or something, no matter how much I want to get intimate with her. (I'm still a virgin... *is ashamed* >_<)
I'm just worried that this isn't "normal" and that I will have problems in the Bedroom which I don't want... :\
I need advice because I don't wanna screw anything up...