I had two recent experiences. One, a feeling of relapse, that I was slipping back into bad habits. The thing to do here is to simply take the next day after that and resume the good habits again. To feel super bad about the relapse is precisely what will make you give up completely.
The other was a feeling of exhilaration. I just felt super good one day. I wrote a poem early in the day, then I had my voice lesson at 9 a.m. and then just floated on air for a good part of the day. I had an egg in my jacket pocket (don't ask) which broke and made a bit of a mess. I burst out laughing because it just seemed such a trivial, comical mishap, and so typical of my typical human foibles.
Exhilaration is not going to be the norm in most of your life. It is a very rare occurrence for me, for example. It happened to coincide with the inauguration so it wasn't at all justified in the larger scheme of things. It was simply a sign that my body was sending my mind that I was doing things that I should be.