Don't feel sexy taking nudes

I used to like taking pictures and sending them to my boyfriend but as of lately I just feel ugly and frumpy. I'm in the best shape I've ever been, and I'm so unhappy with the way I look in nude pictures. One time my boyfriend commented on how my sexy face is kind of goofy and I think that started my dislike not sure why my body image has gone down now. Anyone else feel awkward/not sexy taking nudes?