I need to find a hobby - know of any?

[Beck]

Good time to start exercising.
Doing sports will both get you in shape, take your mind of the break-up, and generally improve life quality.

The other part you mention about doing some volunteer work.... Well, try it out. The absolute worst thing that can happen is you decide that you don't feel you are gaining anything from it, but then at least you have still done some good for other people.