Is this bedbugs or hives? Or both?

I have outbreaks on the tops of my thighs that look like this:http://www.nlm.nih.gov/medlineplus/ency/...
The reason I haven't assumed it's bedbugs is because they haven't bitten my boyfriend (who sleeps next to me), they only bit me on the thighs on the exact same part, we haven't found any bugs, and the "bites" look like hives after I scratch them.

The reason I haven't assumed it's hives is because (although they flared the day after I was stressed) I haven't eaten anything new and I'm not allergic to anything.
Any ideas?

Oh, and I heard that hives can be triggered by an allergic reaction to insect bites, so it could even be both!

Hives can suddenly develop and can be related to stress. You should see a dermatoligist because other skin conditions may exist.

You may not have had any allergic reactions before and suddenly get allergies, it happends sometimes. A few of my friends that have hives didnt get them until there were in there twenties.

Get a new mattress. I have actually read about this sort of thing before, and the solution was get a new mattress and new sheets. Apparently washing them didn't work. The piece I read about it was actually bed bugs and the person spent lots of money trying to exterminate. It ended up this is what he had to do. He described the exact same thing.