I concur with other comments that this can be a sign of burn-out. I've been there as well. However, I never doubt that I'm in the right profession, but I do kn

I concur with other comments that this can be a sign of burn-out. I've been there as well. However, I never doubt that I'm in the right profession, but I do know that, as a human, I'm bound to have ups and downs with any topic that I'm involved in for longer periods of time just like relationships have ups and downs. What I chose for myself is to have some activity that is completely different yet very enjoyable for me and I acknowledge that I do it as a balance and reward. In my case, it's playing the guitar. I reward myself with the occasional gear purchase and generally enjoy studying+playing. Sometimes, I'm super focused on my job and go slow with music. Other times, I'm super into music and I'm fine with sinking less effort into my job. The idea is that I have where to bounce to when I get a bit disenfranchised with one or the other.