What about the clothes you were wearing when you washed the others?
You must SPRAY everything with bug spray, your backpack, your sleeping bag, your clothes, and wash them ALL, including the ones you are wearing. You must spray your shoes. The bugs hide in every tiny seam and crevasse.
Then, you can go to the farmacia and get a mosquito spray for the skin (be sure they don't sell you something for the bites you already have, but instead you want a REPELLANT). Spray your body before bed each night.
If it's hot and sunny, you can also put your EMPTY backpack into a black garbage bag in the sun for a few hours, and that will kill any that are inside.
I'm so sorry this happened to you.
It can be very distressing!