Waking up with countless bug bites?

Hi. Recently, whenever I wake up, I get countless bug bites on my body. They're pinkish, look like mosquito bites, and itch. However, unless the mosquitoes were having a freaking party every single night, that's not exactly very likely. The area that's affected is normally random. Sometimes, it's at the backside area. Sometimes, they're at the side of my body. I originally thought that it was bedbugs, but I couldn't find any traces of it. Last night, something really weird happened. I didn't go back to my room to sleep, as I was rushing my ignment with some friends. We pulled an all-nighter at our faculty, and only returned to our rooms in the morning. So, I did not touch my bed at all. However, when I took off my clothes, I find countless bites on my left calf, and also on my right calf. Can someone help me? It's really irritating, and I would like to solve this problem once and for all.