Mood swings

I´ve been really motivated since having surgery in november and made some speedy progress, but the last couple of days have been kind of hard. Maybe it´s the weather - it´s freezing outside. Also, I feel bad to my stomach.
My bike seems to be coming along fine, yesterday I did 6*5 mins at 400 watts on the bike trainer. My swimming is better all the time, today I did a good 20*100 m session. But my running sucks. It was always my weak spot and now it´s even weaker. Need to work on that.
I might have been too eager hitting off with high intensity work. Maybe I should have patience and do the base work in order not to peak out in march. In part, the motivational down could be due to a bit of overtraining.
Of course, I´m still happy to be able to train and make progress after more than a year´s layoff. Thank God.