You may need to do more digging. Pretend it's raining. Will water run into the shed?! If so, you need to landscape around the shed to re-route your water. Do have about 4" of gravel UNDER the shed for water drainage, and don't put dirt up against the shed. You'll be inviting trouble.
My best to ya and hope this helps.
PS: I put my shed on a sloping hill. I dug out about 2' more behind my shed (the uphill side), and sloped the hill to a 2' gravel 'bed' back there. Underneath the gravel is a 4" trench around the shed that will route water to the front of the shed (or the downhill side.) BEFORE you put any gravel in, lay in some filter fabric. It can be found at a STONE YARD or QUARRY. They're in the Yellow Pages.