Have you actually seen them around the mattress edges or residue from them? Perhaps you got the bites outside (sand fleas, no see-ums, etc) and many times they can even come in through your screening. Have others in your family received the bites?
The first thing I would do would be to toss the mattress and even all the bedding. Alternately, you could try washing the bedding but I'd just toss it to make sure.
Wash all surfaces, vacuum good and make sure the vacuum gets cleaned out good. Then get a bug bomb and set it off - one in the bedroom and 1 in the living area.
Then definitely wash down everything for the residue of the bug bomb. You don't want to set food on the counters with the residue.
Good luck!