Please Tell Me I'm Not the Only One

I am an avid talker. I talk so much that sometimes people tell me I'm rambling. I always have something to say and end up taking conversations every which way you could think of. But, when I'm in front of the person I'm interested in, I suddenly lose the ability to talk. I try and make small talk, but it's very hard to respond to. I don't know if maybe it's because I don't want to embarrass myself, but I just sort of forget how to socialize. How do you guys deal with this?