John,
Welcome to the forum.
You got some sound advice.
Definitely get a colonoscopy.
You've handled this disease pretty well in the last 10 years.
My take on this disease is a little different, because I can't tolerate the mesalamines, and refuse to do the biologics.
In my experience, what's worked for me is a combination of diet modification (as in going gluten and dairy free) - basically PALEO, and some supplements: l-glutamine, slippery elm, probiotics, and LDN.
BTW, did you have your blood serum vitamin d3 checked recently? It might be quite low which is why you may be flaring now?
Are you on any probiotics?
Any special diet?
Anyway, if you are interested, there are things IMO that you can control, which will have a direct impact on
your disease, the symptoms you experience and their severity.
I was able to control my UC into remission through various
supplements, probiotics, diet modification, and LDN , low dose
naltrexone.
For more info on the protocol which has put me into remission,
please go to this link: https://www.healingwell.com/community/default.aspx?f=38&m=1666318 , and look at the 11th post.
I hope you feel better and let us know how we can help
you.