I once read that with general anxiety you get the symptoms first and your mind searches for things to be worried about because you have symptoms associated with worry. Example... stomach upset causes your brain to think "upset stomach means I'm worried...what am I worried about?" Then it starts going through everything you could be worried about which obviously makes the physical symptom worse and the cycle continues. I've found this happens with me but worse because my ocd latches on to the new thing to be worried about.