Dark Cherry Stout - Odd Fermentation

I recently cooked up an extract kit of Dark Cherry Stout. Used the Danstar dry yeast. OG - 1.045. Fermentation started normally. Had the temp around 70-72, for 2 days, then it warmed up here and I put it in my fermentation chamber at 68. Waited about 2 weeks and took a gravity reading, 1.022. I let it go another 3 days at room temp (around 70-72). Transferred to secondary and added cherry flavor. Much to my surprise, the fermentation took off. I had active bubbling in the airlock and even got some foam on the top of the beer. It’s been 7 days and its slowed down again. I am wondering if there was a lack of O2 in my primary, or some other issue? I have never had a fermentation start, stop, and re-start quite this way. I will take another gravity reading when I keg this one (I’m guessing quite a bit lower). Your thoughts?

I dont know if im correct or not but maybe the cherry extract might have sugar in it? The last time I did one with a flavor extract directions said to add it at bottling/kegging.