So, I'm freaking out.
In early September my boyfriend stayed at my apartment (we are long-distance). He had a bed bug problem he was unaware of at the time until he got back home and found bites all over his torso and then began seeing bugs. He subsequently treated his house. I had a bug sniffing dog come and get a positive hit on a piece of furniture in my room. I threw out the furniture (it was an Ottoman) and had a PCO come and inspect the room. They didn't find anything and said the dog hit was likely a false positive. I then encased my mattress and box spring and put climb-ups on my bed legs and sticky traps around the bed. Two months went by. Didn't find anything. No bugs, skins, fecal... so I figured I was fine. You can find the thread describing that process here:
http://bedbugger.com/forum/topic/my-saga-still-dont-know-for-sure
After treating heavily with DE for a month, bagging/heating all his things, etc., my boyfriend thought he'd gotten rid of the bugs. He came and visited me in early November after he hadn't had any bites or bug sightings for four weeks; prior to that, he was only seeing nymphs for a week as the last eggs (presumably) hatched. Just in case, we had him put all his things into the dryer for 45 minutes before he entered my house, except for his shoes, wallet, and phone, which we sprayed down with rubbing alcohol.
I didn't have any trouble after that either. I then went to his house for Thanksgiving (again, treating all my things in the dryer or with alcohol upon returning home, except for a couple of books, which I couldn't really do anything about...). At no point since September has he seen a bug. However, I was just sitting in the library at my university and took off my wool sweater to find a bed bug (I know what they look like by now; I saw live ones in a jar that the PCO had who came to do the dog inspection) on my undershirt. It was alive. I grabbed it and flushed it down the toilet after snapping a couple of pictures.
Now I am HORRIFIED, disgusted, and don't know what to do. I've been out of the house all day and was sitting in a coffee shop for a few hours and then my school library for a few hours. Could it have just been sitting in there not biting? Is it common for them to hang out on people? I also have a fantasy that there's some bizarre coincidence and one climbed on me at the coffee shop, though I know that's very unlikely...
My most important question is this... since I probably have an infestation... How long would it take for one to develop from a single egg-laying female? Is this an issue I may potentially have had for months? Or something new, from the Thanksgiving visit? How likely is it that I'll keep finding them on my clothes?
I am doing my finals for school and am terrified. I don't have time to deal with an infestation this week... Can someone give me any comfort or advice? I'm going to call the PCO tomorrow...
ETA: I know it was probably stupid to see my boyfriend at all after he had only gotten rid of bugs four weeks before, but I was kind of at a loss as to how to deal with the situation. I wasn't going to break up with him... and I know that there's nothing I can do right now, but any responses would be really helpful... How likely is it that a hitchhiker bug created an infestation in a couple of weeks?