I don't know what's wrong

About 6-7 months ago, I started to devote more time to my chess and work to get better. I went from 1500 to 1700 in about 3 months, and I was pretty happy with my progress. I bought some books, and have been looking at those, and in addition I've been watching videos and really trying to get better.

But starting a little over a month ago, I've started on a horrible losing streak. I studied some more, I took breaks, I got better sleep, I reviewed my games, but nothing that I am doing is working. I'm close to coming back down to 1500 and I don't know what to do. Some days I do really well, and play some great games, other days (today, for example) I find myself sitting there and literally having no idea what do to. Please, any advice would be greatly appreciated.