Early Adult Anxiety Disorder?

This is one of those things that I find hard to describe...so please bear with me.
I鈥檓 an 18 year old male, I鈥檓 relatively popular and well liked, I鈥檓 active in my school, and I鈥檓 attending a post secondary institution next year. I have also been dating a remarkable girl for almost 2 years now.
My problem is this: I have no rational reason for feeling the way I do sometimes...I have this constant feeling of doom and dread that she (my girlfriend) is going to leave me for another guy, which she constantly reminds me that she wont. But I get this feeling in my stomach and head...like pressure building up. When she is out with her friends I鈥檓 constantly worried about her. Lately she's been on msn a lot (she never was before) and I feel like she is going to leave me for somebody she falls for online. I feel so pathetic, and she says that I don't trust her (in my head I do, I trust her with my life) but this is getting so bad I can't sleep at night, nor function during the day.
Please help!

You sound a lot like me, I was struck down w/ Generalized Anxiety Disorder earlier this year for no apparent reason, I have a good life, great family, etc. That's the bad thing about it, it will happen to anyone at anytime for no reason at all, I lost over 10 pounds, b/c I had no appetite, and I was so depressed and didn't understand why this was happening to me. Go see your family dr, I put off going for months, but after I did I felt so much better and am slowly recovering. Good Luck.

Speak with your Dr or school counselor you dont want to ruin a perfectly good life and relationship with insecurity...dont ignore it deal with it.

wow, this might sound strange coming from a girl but hey i can try to help, can't i? you need to chill. seriously. you need to stop worrying about things you can't do anything about. you can't control what she does and you can't know what she is doing all the time. you need to stop feeling the way you do. if you really suspect that she will leave you for someone else, then you should have reason to support why you think that. you need to get over your fears and if you trust her, then you should believe her when she says she wont leave you. if it helps to know, i suspected my ex-boyfriend was going to leave me for someone else, he didnt though, he left me to live in Russia...