Wash your mattress pad.
Hopefully after my sheet washing post (if you missed it, click here to read), you've gotten in the habit of washing your sheets every week. If you haven't, I'm assuming you didn't read or get fully repulsed by my bed bug post?!?! If you missed that post, read it here).
Anyway -- my hunch is that although you may wash your sheets, you don't always wash your mattress pad. Good news is that you don't have to do this nearly as often as your sheets but you definitely can't neglect it.
Cotton pads are usually machine washable and dryable but make sure to check the label first, since down or foam pads be be dry-clean or spot-clean only. For small covers, you can wash these in your home washer on warm cycle with regular detergent. If it is white, add 1/2 cup of bleach to the wash cycle. If the mattress cover is colored, use a color-safe bleach to the wash cycle. If you do not have bleach, add 1/2 cup of borax to the wash cycle, which will also help to eliminate dust, allergens or bacteria that may be present. Tumble dry on low with fabric softener. Waterproof pads can be machine washed and dried as well, but skp the softener - it can destroy the protective coating.
If the mattress cover is large or heavy, for instance, one used on a king-sized bed, it would be best to take this to a laundromat with washers and dryers that can accommodate large items, thus eliminating wear and tear on your washer and dryer.
You should aim to wash your mattress pad once per month so start this week and make it a monthly priority to keep those bed bugs from cuddling up next to you!