Regarding men--I overnalyze too much & therefore I can't trust my intuition?

I am 40, yet can never trust my gut instinct. I usually am right with it, yet I sometimes am not. I overyze things to death. My friends who are outsiders and perceptive, tend to side with what my gut instinct is, but then I get negative and to prove them wrong, I turn into Dr. Jekyl and say that the man I'm interested in couldn't possibly be interested in me. This happens to me in dating, in relationships and when I first get to know a man. I then sabotage my relationships by getting paranoid, thinking the man doesn't care for me, following my negative side instead of my gut instinct. I haven't had success in romance, so that is why I am so negative. I seldom even let my gut instinct rule me, so I really can't say if it works. If a guy flirts with me, I wind up saying in the end, "No, he isn't flirting with me, he just thinks I'm like a guy friend," even when he doesn't flirt with anyone else. Your thoughts?