I've downloaded the photo and blown it up enormous, but it is still just a black splodge. I think you'd need specialist equipment to take a clear picture of something that small.

But I am used to seeing lots of tiny little black splodges like that in gardens, etc, and I am not aware any of them bite. They sometimes hang around in a cloud under an overhanging tree, and then cover you when you walk through. To me they usually look rather like a beetle, although hanging around in the air seems an unusual habit for a beetle. Maybe they are actually something in the hemiptera. People often suggest thrips for these small black aerial bugs, but having looked at pictures of thrips I think usually not. But basically what I'm saying is that these are unlikely to bite you.

Fleas can get in your clothes, so they bite you where you have clothes on, so in general not on your hands, feet and head. When I got them in my woolly socks, they bit on the ankle, not the foot, because they did not want to go in the shoe and get squashed. But if you are being bitten all over, then bedclothese seems more likely. But I wonder about bedbugs? Fleas can also get into furniture, carpets, etc, usually off dog, cat, etc, in which case they may bite opportunistically. Though I think cat and dog fleas can also colonise humans, in which case they tend to like hairy corners like the groin.

What you do to get rid of fleas in clothes/bedlinen is wash all the clothes they might have got into and hang them out on the washing line in bright sun. Then you put those clothes/bedclothes on, and do the rest. For fleas that may have originated in dog/cat, take advice from petshops, as the method of dealing with it depends upon whether it is dog or cat. For mattresses, you'll just have to spray them.

If bedbugs, no doubt you can research that.