Loss of an activity you love, is hard to adjust to. I had to give up my career, which hurts to this day. I looked down into a magafier to create miniatures. Now that I am fused, I can't look down to do the scuptures. So I changed and do mosaics looking forward on an easel. I walk alot too, though I never did run.
It is a question of finding a substitute, something that gives enjoyment, even if it is not your favorite. Lots of adjustments are made to compensate for what we lost. It takes time, and some real thinking to make some changes.
It is OK to be sad Chelk, you are experiencing a big change. You are going to find things to do that you didn't even know you liked. Just keep moving forward, and more things will present. I grieved a long time before I found things to give me joy again. The ever talked about bucket list is another goodie. Write down all the things you can do, that you may want to do, and get to it. Maybe a concert you always wanted to see, or an outing in some location you always wanted to go to. Just keep trying and you will find ways to bring joy again into your life. ginnie