try to busy yourself with something, that way you won't leave as much room for negative thoughts. learning languages is one of the options. it requires discipline, which if developed, helps to get the motivation and determination for other things you might want to do. as for motivation, i often rely on thoughts like "i might be walking to the store tomorrow to get my daily dose of sugar and get hit by a car and NEVER finish learning that language" or "i've lived xx years and did jack shit so if i continue like this i'll live another xx years doing jack shit"
this method has been proven by me, a random user that just joined this forum.
on a more serious note, i hope it passes soon (which it will, eventually) and you feel better