Strugglin' - yes indeed, winter seems like that every year to me.
BUT, spring is just around the corner, stick at it and get some more miles in. [Hello sky, hello sun, hello flowers...]
Sometimes you just have to force yourself - a plan helps: a new route, go further afield, train for a seriously hard event, ride with your mates more. Run some longer errands, shopping in the next town etc by bike...it all helps.