How illusive are bed bugs?

I have bites all over me and itching all over (even my dogs are itching), in places that bugs outside would not normally be able to get to with clothing on. I also just got back from a 2 week trip where I stayed in several hotels. However, I've stripped my bed and inspected it, pulled the bed out from the wall, etc. and there is NO evidence of bed bugs. No bugs, no eggs, no blood, absolutely nothing that I can find. Is it possible they are just well hidden and it's not far enough along to find blood or is it just bugs and plant poisons from outside?