Yes I definitely have felt this way. It's an awful feeling when things I normally would enjoy no longer bring me joy. During this time I just force myself to stay on my routine. Going to work, going to the gym, going to see my horse, eating healthy etc. etc.. Eventually the depression does lift and I start feeling more like myself, but I find if I don't continue with my routine the depression gets worse. I also found when I was initially diagnosed I could no longer rely on the unrealistic hypomanic energy. I was undiagnosed for so long that I thought that the hypomania was me and I just was more dedicated/motivated than the average person.

A good way to start is to do something that normally would bring you joy. Exercise really helps because it increases those feel good endorphins. You may want to just start with a brisk walk outside for 10 minutes and build up from there. I use this trick that I will tell myself that I can do cardio for 10 minutes and if I still don't feel like it I can stop. Most times after 10 minutes I start feeling better and have the energy to do more.

The lack of motivation may be an indication that your meds need to be changed or tweaked. You may want to discuss with your pdoc. I also find seeing a therapist helps. I hope you start feeling like yourself soon