Hello, I'm Alicia. Thanks for your question, I'm happy to help you today.
I don't know for sure, based on what you've said here, if it's necessarily an anxiety disorder you're suffering from. It's certainly possible, especially if you have other troublesome symptoms (i.e. excessive worry, feelings of panic
, etc) but to truly be an anxiety disorder you need to meet specific criteria, and there are different types of anxiety disorders, too. (you can read about those and their specific criteria here: http://www.nimh.nih.gov/health/publications/anxiety-disorders/introduction.shtml)
That being said, it sounds to like you might possibly be getting scared off by the idea that you DO actually like these guys. Maybe it's a fear of intimacy - even though it sounds like that is the very thing you want, it could be the very thing that you fear the most because you (well, we all do) want it so much. It's kind of the same thing as a fear of success - which doesn't sound like it should make logical sense - but our emotions rarely make logical sense!
Feelings of doubt are normal, especially in the beginning of relationships. It's normal (to a certain extent) to ask questions like the ones you mentioned, i.e. "hmmm are you sure about this? are you sure this is the right guy?" One thing that strikes me, though, is that your feelings of anxiety might be stemming from the fact that you seem to place a lot of pressure on yourself -- and on the guy -- to be the "right" one. It's normal to ask those questions, but it seems like you're getting way ahead of yourself. Especially since you just started dating this new guy last week - these are questions you should be asking months from now - once you actually get to know each other. Right now you should be enjoying the process a bit more, getting to know each other, and having fun in each other's company. Try not to build it up to be such a monumental thing - because, to be honest, that is a likely factor for your feelings of anxiety.
Don't beat yourself up for feeling this way, and realize that everyone feels like this from time to time. It's hard to get a handle on your emotions, especially when they start to take on a life of their own, but once you realize why this is happening, you might be in a better place to get a better handle on your emotions and just relax about things a bit more.
If you still think it's an anxiety disorder, however, and there are other symptoms you're experiencing, then the only way to know for sure is to have an evaluation by a mental health professional in person. You can find someone in your area on this website (and sometimes, it can be helpful just to discuss your feelings with someone, even if it's NOT an anxiety disorder): http://therapists.psychologytoday.com/rms/prof_search.php
I hope that helps. Please let me know if you need further assistance.