I understand this completely.  I've been working out every other day (and with a trainer once a week) for several years.  I have never, not once, felt good after a work out.  In point of fact, it's rare that I don't actually feel bad.  I've been to doctors and tried different times and foods and many other things.  Nothing seems to make much difference.  I still do it because I know I need to (my work is a desk job and fairly sedentary), and I'm in pretty decent shape, but if there was a way I could quit without compromising my health I would do it in a second.  All that said, keep in mind that I am still doing it and have no plans to quit.  Exercise is *that* important!