Fleas and bedbugs both suck blood and can leave you with red bite marks when you wake up in the morning. Since they are handled in different ways, it helps to know which you are dealing with. Fleas tend to be attracted to pets more than humans. Bedbugs tend to be attracted to beds, where they can suck your blood during the night.
Check for dark spotting or staining on your mattress. This may be the excrement of the bedbugs.
Check for blood spots on your linens, which can result from your rolling over onto bedbugs and crushing them after a feeding.
Check the mattress, especially around the seams, for the actual bugs themselves. They are brown, flat and the size of ladybirds.
Use a screwdriver to see if you can scrape out dead bedbugs or their shed exoskeletons between the carpet and the baseboards.
Look for small itchy red bumps on your body, especially in a line or in clusters, which indicates the sequential feeding of a single bug. The clusters will not be confined to any one part of your body. Flea bites, by contrast, will tend to be concentrated at your ankles and feet.
Test pets for fleas by patting down their fur with tape. This may pick up fleas on the adhesive side.
Slide across wood and tile floors in white socks, especially around areas that your pet lays. Fleas' brown bodies will be easy to see against the white background. They sometimes can even be seen jumping onto your socks.
Notice if your pet is scratching itself a lot. This suggests the red bites you suffer are from fleas.