I've been in a very mature and positive relationship for a little over nine months and over Christmas realized it could be long term. I love the feeling of being in love with my girlfriend and being there for her.

This month, I've felt like I'm losing my mind and worse, my heart. I've had daily intrusive debilitating thoughts and feelings that I will lose my relationship. There have been several lines of thinking, ranging from fears that I will cheat, that a possible marriage will end in divorce, that my occasional same-sex attractions will preclude a long-lasting relationship, that I will hurt my girlfriend emotionally, and that I will simply lose all attraction. This is often constant: hour to hour, day to day. The thick of it feels like death. When it goes away for a while, I feel silly about how I felt.

It all followed a discussion with my family about the upcoming semester, during which they mentioned the idea of engagement. They were right, I realized. She's amazingly compatible with me in the best kind of way: personality, sexuality, interests, maturity. I love the feeling of being in love with her. I am in my final semester of graduate school, and so a new chapter of my life is fast approaching. It's time to move forward.

Soon, I weirdly started to worry and fret about various topics, listed above. With this came a gnawing dread which, in a flash, replaced the wonderful feelings I had for her. A depression set in hard. I felt numb toward life, family, and most frightening of all, her. These intrusive fears felt nothing like the normal doubts that I've had in past relationships, even when I've contemplated breaking things off. I suspect that a big part of this is the stress of entering the next chapter of life, but why it's causing these symptoms is beyond me. It's like part of me has been slashed out. Unless very well distracted in the mind, there is constant anxiety, constant thinking, constant cinching in my stomach.

It got worse. I became fixated on the idea that I was going to become gay and have to be with a man. This has been the scariest, most unwelcome, thought. Male friends who I have known since childhood became the objects of really confusing feelings of attraction and anxious intrusive thoughts. Soon, every guy I saw made me compulsively have sexual thoughts or fears. I never wanted this, and am so confused and constantly down. Orientation isn't supposed to behave this erratically.

My occasional same sex-attractions haven't been something that really bothered me until now. It never seemed like a big or important part of me, just another character trait. I've never really worried that I'd have to act on such interests. Now such thoughts are suddenly killing me.

My mind has raced through so many ideas of why I cannot stay with my girlfriend; one that was running last week was: "you must first get with a guy, before you can ever feel better about her".

This wasn't true, and I've had several very fun days with her. Sometimes I almost pop out of the woods and it's bliss. My girlfriend is entirely in the loop on ALL of this, and she has been amazing in taking care of me. Even when she's scared too, she's there for me. When stress in life goes down I can actually feel my fear and doubts about us take care of themselves and my happiness/satisfaction shoots up. . I'm so afraid it is all slipping away; that the good feelings won't come back next time.

I have been in one other long term relationship. We cared about each other. Shortly after she unexpectedly broke it off with me, she came out to me as lesbian (a few years ago this month). At the time I didn't think it bothered me, and it still really doesn't, consciously. In the past I had one other episode similar to this where I lost my faith. My anxiety says that means I'm losing my girl too. That I have to lose her. That I want to lose her but am too stupid or cowardly to just pull up my bootstraps and dump her.

I want to take the right steps to level things out with my girlfriend. She amazing to me and I hate to make her sad, feel empty toward her, or constantly feel like I'm draining her. I just want my heart open to her love again. I don't want to obsessively fret myself into no longer loving her. I don't want to lose such an amazing girl. It's like a heavy fog.

Any guidance on what's wrong with me?