This may be kinda longer than most posts here but I truly appreciate ANY input you guys might have that could help me.

I'm just looking for opinions here, because it's beyond my understanding. I've posted here before regarding the same problem but in different contexts. Recently, there has been several occurrences that are legitimately making me question whether or not there is something wrong in my brain. During a day in my everyday life, I'm usually presented with 2-3 opportunities to have a potential interaction with attractive girls. Of these opportunities, some of them are so blatantly obvious that this girl wants me to go up and say something, but I can't do it. And EVERY SINGLE TIME I feel terrible about it... Fucking horrible. This is why I feel like something might be wrong with me. Isn't it natural male human instinct to try and have sex with girls? At what point will this instinct overpower my misplaced inhibition of approaching? I know for 100% fact that girls find me attractive, but I still am unable to do it. When I'm by myself, at my house, or in my car etc, I tell myself that I CAN do this and that I'm confident, and I truly do feel that way for that moment. However, when the time comes for action, I just always get this sick feeling and/or can't think of anything to say.

Now, with all of this said, I'm expecting that most answers will be along the lines of: "Nut up and do it." Trust me, I tell myself how fucking stupid and cowardly I am all the time after realizing I passed up a chance. Sometimes I break things. It's getting progressively worse and I'm going to end up hurting myself one of these days if I don't figure this shit out. I know this may sound overly dramatic to most people but just the very fact that I'm WASTING my years and good looks by not being with girls is driving absolutely insane.

Like I said, ANY advice will be graciously accepted. Thanks guys.