I talked to my sports specialist and my doctor about this very issue. Many of your observations are more real than you might think. Weight gain over the holidays, combined with cold weather can have a lot to do with it. The mind can have a lot to do with it if it is a one time event for a person that normally climbs like a cat. But if it lasts n=more than once or twice look towards other reasons. Cold weather effects muscles and breathing, says both my doctor and gym trainer. To what degree depends on the person. Time off the bike effects different people differently. Need for rest and rebuilding is also a consideration. Why would I think this, because I have had exactly the same results as you after the first of the year. I figured it was the traditional winter let down and weight gain. Then last week I had one of the best rides in a long time and posted two of my personal bests on Strave one of which involves a climb, which I normally suck at. Two days later is was in the small ring and spinning again on hills I had motored up in the big ring only a month before. For me it happens every year at the same time or within a few weeks of the same time every year depending on when we get our coldest weather. My trainer said it was normal and would be a good time to cross train, get rid of the Christmas weight and give my legs time to recover. With the coming of warmer weather things should go back to normal. That is how it works in my case anyway. Just a thought, but maybe that is why they give racers an off season? None the less I don't think from the way you describe it that it is simply in your head, otherwise after the first successful recovery ride you should have been back to normal. Check out this site and see if it helps. http://hss.edu/onthemove/5-ways-weat.../#.UQgxmr-YuSo