Most all species have periods of molting or shedding or hibernation or whatever you want to call it. Some of the most beautiful feathers grow on a chicken after they have gone through the molting. I'm not saying you're molting, but it may FEEL that way right now.......
This feeling can be turned around, though, it really can. I believe this. I've seen it happen. Just when the caterpillar was losing all hope it turned into a beautiful butterfly. Some days are warm. Some are cold. The "air turns"...or so it seems. Turn it around. Do the opposite as what you feel like doing or what you usually do ... stretch out...try something different.
One of the best/first songs I ever wrote I remember feeling/thinking "I can't write songs!" Til one day, someone/something told me I could if I take the time and TRY IT. I entered "the zone" and the words came forth eventually and I was alone.....or was I alone, really?