D.P.
Bed bugs do not typically live in storage sheds (as there are no human hosts that live in those areas). Did you put some bedding in there, or some old suitcases that they could have crawled out of? I have heard of some other species related to bed bugs that feast on swallows and bats. Call an exterminator and look around for nests of any kind around that shed. Getting rid of the nest (if you find one) might help.