Thanks for all your replies
I do not think it can be cross-contamination since I have used all the equipment for other things since I last used them with gluten and have not become ill - I use the same pots and pans for everything and cook 3 meals a day with them, none of which have made me sick.
I also have not had any other gastro symptoms from dairy, just burping and pooping a little more often. I still get GERD symptoms from time-to-time, but they didn't really accompany the burping from the bread today. Belching is at least fairy minor - socially awkward but nothing that is going to cause too much pain!