I'm having trouble feeling emotions and the quesiton "Am I gay" keeps popping in my head even though I know that I want to marry a woman and have kids?

Now I can explain more. i guess this is the area this topic would go. But anyway, I've always been attracted to girls I'm in love with a girl I've known for the past 5 years. I know she's the one I want to marry and be with the rest of my life. However, even though she says she feels the same way, we're not dating. Since October I've been having erection problems, I seem to have a low sex drive and there's no more looking at attractive women and thinking thoughts that would turn me on and it happening. When I do get the erections they don't usually stay and are hardly complete? Well recently something has happened, I don't know what and I can't even remember when I just know it started happening around Monday or Tuesday and it hit me about thursday. But I'm seeming to have trouble with emotions. I know I love her, yet when I'm around her nothing registers emotionally or physically just the fact I get mentally where I know that I couldn't stand to lose her. It's hard for me to get happy, mad, excited, or anything like that. But, then sometimes I can feel these emotions and they constantly flip back and forth. I'm not turned on by guys, I'm sure of that. I change in locker rooms with other guys and I've even seen one naked. That was at drill by the way when the rest of us were changing and some idiot decided to walk out of the showers completely naked. Nothing happens when i see this, I'm not attracted to them. However, I've tried looking at all kinds of porn and gay porn tends to turn me on sometimes. But as does lesbian, and just guy on girl. I don't understand what would cause this to come on really fast. I talked to a friend last night who is bisexual and he said that he thinks it may just be that gay porn is something new to me because i watch so much porn, and that it's just a phase. But i don't watch porn alot, maybe once every other day or so. I think the problem is, or atleast I know it scares me. Whatever is causing me to not get an erection is scaring me. I know i love this girl yet i don't seem to be sexually attracted to her since october, even though i always have been and I know that I would have sex with her. Is it something to do with watching porn? Maybe visual stuff doesn't turn me on anymore because I've watched it so much? And the gay porn might because it's not something i've always watched it started sometime after october so it's kinda new to me. I watch all different kinds when I do btw. But besides that I'm not attracted to guys. I can walk down the hallway and not be attracted to any guys. Sometimes I'll see a guy and be like "well atleast that girl isn't dating anyone ugly". This is just scaring me because it's against my beliefs. I've always been against the idea, and I believe that the part of a man matches with the part of a woman for a reason. Could it just be phase? The idea me and my friend came up with was (the one who's bisexual) stop masterbating for quite awhile and everything will come back. I know that I want to be with a girl when i grow up and have kids to carry on the bloodline. The girl I'm talking about seems to think the problem is from stress causing depression. I don't know about being depressed but I am down about a couple things. Here's a couple things that bothers me, and i'll let you be the decider. I'm sad about the fact that I'm in love with an amazing girl who says she feels the same way about me. I'm annoyed/bothered by the fact that we used to talk alot every day, but now we talk about 1 pd out of the school day and about 30 mins on the phone at night if i'm lucky. Even though she says she wishes we could talk more. The reason we can't talk more is her bf. He doesn't like me simply because of the fact that I'm her friend, and that annoys me. It annoys me when I can only talk to her one time in a day and he steps right in and takes her away. It annoys me that he wants to fight me just because I'm friends with her.

Maybe it could be something to do with her....last time I was actually turned on by a girl in school was when I was with her. Probably September or late august. It was homecoming dance and just her dancing with me and us kissing got me going. But since then nothing has happened between us and I have felt nothing. Any ideas? Prefferably from someone who is a doctor.