Sounds exactly like an immune sensitivity to something, could be food, could be yeast or die off toxins. Those are all igg reaction symptoms and thats the only thing that could be responsible for that quick of a remission as well. Ive experienced exactly this more times than I can count. Try a rotation diet to see if you can nail down any/what foods and up your fiber intake and add a little bentonite or charcoal to your daily routine to absorb the toxins. Try to avoid that happening as much as possible because it is really hard on the body and immune system and will reverse any healing that should be happening.