I had my surgery almost 2 years ago. Dumping has never been a consistent problem for me, but I think it started up probably about 6 months after my surgery. I was very worried at first, thinking I'd have it forever. However, after a little more healing, it calmed down a lot.
Now I just get it randomly. I can always tell when it's about to hit--I get very loud noises from my belly. It's funny...I thought it was related to roughage/raw veggie or salad in my stomach/irritating my wrap, because that's when it has happened the most. However, I have had a couple times when, like you, it's all about a cookie or something. Other times I can eat any amount of sweets I like, and I'm all good.
You certainly can have hope that it will calm down soon. I get it maybe once or twice a month. It seems streaky...I might go a month or two without it, then have one or two in one month. When it hits it doesn't last long, though.
I hope yours settles down very soon. I expect it will.