I am glad to see that biking helps you. Personally my (almost) daily short ride (5 to 10 miles) has been I think literally a life saver. I cycle normaly by myself on a recumbent Terratrike. I greet almost everyone with a smile and a "Good Morning!" as a part of my "therapy" and at least 50% reply equally cheerfully. It is hard to be depressed when you are smiling and exchanging pleasanteries! I also mutter "positive affirmations" to myself several times a trip.....muttering "no pain,great muscles," etc must sound wierd coming from an almost 80 year old man with scoliosis, stenosis and neuropathy BUT it actually helps. It is all to do with neuroplasticity I think. It wasn't easy in the beginning of course but after a few weeks of tears and blues on the trike and studying mindfullness in the evenings my brain "clicked into gear" and the daily chore of cycling gradualy became something I looked forward to. I often take coffee in a flask and a book with me and have a break soaking up the sounds of nature and reading for 10 minutes or so. (This might be more difficult if you live in a busy Urban area but there are often parks, church yards and the like.). All the best for 2020!