I'm sorry to hear you are going through this. Yes, a break up can be a very stressful event that could trigger a flare up. Every time I have a flare, my GI asks me if I have been under a stress. GIs know a big stress can trigger a flare or even a first flare.
A couple of days seems quite fast for a remission (if you were in remission) to turn into a flare though. Thats my only hesitation or questionning.
Stress can also cause GI issues in healthy people and also to us when we are in remission, so IBD unrelated. Stomach and colon can be very reactive under stress. Some people constipate, others have overt and strong diarrhea. So there's also a good chance you are having stress related GI symptoms, unrelated to IBD. Its a possibility which I hope for you.
Try to relax as much as you can, get help from professionals to help you go through this break up if that could help, talk to friends. Breathing and relaxation exercise on youtube can be good too to ease your abdominal region.
So yes, keep a eye on this and dont hesitate to contact GI if symptoms persist.
All the best to you