what are these little guys? help!

My husband and I keep waking up with small itchy bug bites, especially around our waists and arm pits. We thought it might be bed bugs although we never found any visible ones. We completely striped our bed, washed all bedding, had an exterminator come and he couldn't find anything, he set out bed bug traps that came back empty. So I think I can rule out bedbugs.

I found a few of these little black bugs. Some of them look like they have tiny wings but I haven't seen them fly. They are so small like the size of a sesame seed. But look kind of beetle-y. What the heck are these things and are they what's been biting me?! We live in coastal Northern California in a pretty old wooden house. We have a dog that sleeps in our bed, we've checked her for fleas and haven't found anything on her. Would love any insight on what this is and how I can get rid of it.