Walking and/or running. even if you do small and irregularly it helps. if you are consistent then it make significant impact on the way you deal with stress and several other issues. It tool long time to realize this, but for me it works really well for me.
Please get professional help, do no underestimate the importance. I do believe another undertaken advice is around hitting the gym.
Try to find the root cause.
Write down every small tasks in your mind into a notebook and clear them one by one.