Bed rest is bad for my thoughts

I'm sitting in my bed right now. I'm bound here for the next couple days unfortunately. Doctors orders because of my kidneys:/ But that's besides the point. The thing is, when you have extra time on your hands you tend to think a lot. Maybe too much. It seems every conversation, every thing I've done this past year keeps replaying itself in my head. All the mistakes I've made, every wrong decision. All the pain, physical and emotional. Every tear and every nightmare. They live within me right now. I find myself analyzing everything. What I could have done to prevent any of it? Could I have made it better? What would have happened if I made a different decision? So many questions. I realize that none of this should matter. Nothing can change the past. Yet here I am irritated by it. Replaying it all over and over again. I know I should change the direction of my thought's, but doing that somehow seems near impossible. I'd give anything to fix it all. Make everything right.  Do things a little more gracefully. Be a better woman. I am so ashamed of the person I am now. I feel weak, and sometimes worthless. What about me is worth wild anymore? What have I accomplished?  What have I done with my life worth being proud of? I almost don't blame all the people who've walked away from me. Why stay? I'd have left too. I know I'm coming over extremely pessimistic right now. I apologize. I wonder, why is it you can't remember any of the good when you're feeling extremely bad. Like your mind builds a concrete wall to block them when you need them the most. Instead it lets all the negative feelings and memories flood your entire being. Weighing you down further until you almost feel pinned permanently by them. Ugh I cannot wait to be off of bed rest. My mind seems to be my own worst enemy. I need to be productive. I can't take being so still for so long. It just reminds me of how unhappy I really am :/