Have you seen them? What do they look like? I too am recovering from a "bed bugs" problem, but it turns out it's not bed bugs that are biting me, it's fleas. They are smaller than ants in size, impossible to catch (unless you pick them while they are still biting you), impossible to crush.
I let my mattress sunbathe, but it didn't affect them. I am getting a new mattress but for the meanwhile, my mum has put some sort of leaves under the sheet which has, surprisingly, stopped them from biting me.
My left arm, which was full of red bites, disgusting to look at, is now normal again.^_^