Hi and welcome,
There are many different and much more common medical explanations for what you've described is happening during the winter months than MS would be, so I wouldn't assume a neurological condition like MS would even be your list of 'most likely' explanations, when there are many unrelated explanations for these types of common symptoms.
IF your mental health is currently up and down, I would strongly suggest you don't 'unconsciously' make things worse by worrying and reading about neurological conditions like MS......make an appointment with your family doctor and remain very open minded about the cause.
Cheers...........JJ
Somethings could be MS and others not. I would go to my Primary Care Doctor and ask for a neurological exam. This is reflexes and such. If he or she sees something abnormal they can send you to a neurologist. If it is normal they can steer you in another direction.
Alex