I feel your pain, literrally, I was diaganosised also while I was pregnant. Not only do we have the stress of everytday issue of being pregnant, staying healthy, and doing EVERYTHING right for our babies, now there is new "life changing" lifestyle that was added to it.
You are not paronoid first and foremost. You are about to be a new mommy who wants nothing but to keep your child safe from harm no matter where its from. While I was in transittion and trying to find the "hidden Gluten", which there is alot of it, I ended up taking imodium, every now and then until my system got use to it, but most of the time I just hydrated and got thru it.
As far as gummy bear vitamins, I don't know I used proVitmains that say Gluten Free right on the label. Also, I was like you and started seeing my symoptoms subside and I am not a doctor but you are probably correct in that you have eaten something that has been cross contaminated. I ended up buying all new pots and pans, dishes the whole nine yards since I was so misserable, but if your pocket book can not handle it I suggest doing alot of research, reading labels, educate frends and family, reading labels, educate friends and family, oh and reading labels. It can and will be overwhelming espically during pregnancy and all the lovely cravings that we get. I ended up turning it into a came and tried to make my own gluten-free version of Pizza pockets and what nots.
Stay strong, it is a overwhelming task ahead of you to master this life style but in the end it will be well worth it. By the time you hold that baby of yours in your hands your tummy will no longer be a issue, which will make your most important life style change that is about to happen even more wonderful.