Bed Bug Problems- HELP!?

I came back from a trip (Aug 21) and woke up the next morning with a lot of LARGE bites. First I thought they were mosquito bites but later found out, do to the location and the way there were places, that they were BB. After two days of dealing with that, I moved to another room. I later found out that that was the worst thing to do since they can move to my new room and cause a large scale infestation. HOWEVER, the bites weren't mosquito like LARGE bites, they were relatively small red bumps which don't itch. So I vacuumed all the rooms, removed the sheets and wiped down both beds with wipes. I even ironed my new room's mattress when I panicked. (all happened in mid/early Sept)I called Viking in to check it out and they couldn't find anything what so ever. Since then, I've been wrapping myself up in a burrito like style and am wearing as much clothing as possible. That actually worked, I think? I get, what look like, pimples on my face so I can't be 100% sure. I still sit in my old room to study but don't get any bites. Until today, when I received three bites on my right arm and only realized it when I started itching my arm. Again, I re-vacuumed. So here's the question: Why is it, that after 1 full month of no bites (old room), that I am only receiving BB bites now? Came home at 2:30 from NJ transit and only started to itch it at 6:15. Did I, maybe get them from public transit? Q2: Why is it that the size and reaction of BB different? ( From my old room to my new room.