I caught feeble limb, drains my strength. How can I cure this and any other future disease

There are plenty of options, but this covers most of them:

Eat a piece of mandrake root.
Drink a cure disease potion that you can find/buy.
Make a cure disease potion with a little alchemy skill.
Learn a cure disease spell (takes quite a bit of restoration skill).
Pray at the main altar of any chapel (your fame must be at least as high as your infamy).

More detailed info if you like: http://www.uesp.net/wiki/Oblivion:Cure_Disease