Yes, it does take a while to stabilize! And it's the IF that gets me everytime. Actually, it's not the IF, but it's the way I eat IF foods: too much at one time! It's taken me years to figure out the balance, and even now I mess it up. I don't have any exact measure (so, please, no one ask me about SF-IF ratios )- I've just had to learn my limits and always remember that as a D the more SF the better!
I was stable for a few years--I actually thought I had this thing beat, but then I got some bug going around the office and it's taken me more than a year to recover.
Anyway, sorry to go on so long. I hope you get stable soon and that you stay that way as long as possible.