Interesting findings altough it completely makes sense. My prolactin was only 11 in january when I was still in delayed sleep phase with almost no sunlight and my TSH was the same as yours was. I've since restored my circadian rhythm to a certain degree by chronotherapie and now wake up in the morning around 8.30/9.00 and start my day with bright light therapy of 10000 lux. I also go for a walk about an hour a day so I'm already implementing what you're advicing. It will be interesting to see what my prolactin is now but it's no guarantee it will be lower altough it should.
I always think of it as "whats reasonable?" When seasons change we get less light, right? Trees shed, fruit has fallen, animals hibernate, tons of things molt or shed or just quit. Then when long sunny days are back everything is luscious again. Im certain its a big part
Please let me know what your results are, especially since summer is coming