Ups and downs are part of life.
Ups feel amazing and are good for our sense of confidence.
Downs are necessary for re-evalutation and growth. They cannot be avoided, nor should they be. The more you try, the more you resist, the more you sink.
I guess ups and downs are like Ying and Yang, you can't have one without the other :-)
When I start doubting, I try to remind myself the big picture and enjoy the process.
Have a nice week end.