All the time for me! And even if I feel at my best, I am looking for any symptoms to make sure I am ok. But of course that makes me more anxious and it's a sad cycle. I remember the time when flus were nothing to me and I'd go to school so happy with a 100 degree fever... life was so 'easy' back then! Now if I eat too less, eat too much, sleep too less, haven't released at the bathroom, something is wrong with me!