I missed this post yesterday.
Commiserations.
I suspect that your ulcers may be a (that is, you) reaction to sustained stress - because, at the moment, you have been experiencing the tragedy and trauma of attending an online funeral for someone to whom you were close, plus the effects of the Covid vaccine - but, you've had them (ulcers) before.
My sinuses go nuts when I am under severe and sustained stresss.
This has been a rotten time for so many people.
Again, I feel for you.
Not that long ago, I had a lengthy chat with my German sister-in-law; her father (to whom she was very close) died just over a year ago in Germany, and, she missed both his death and was unable to attend his funeral, except online. Awful.
A hysterectomy in late summer - when travel might have been possible - followed months of sick leave & a very slow recovery (she teaches German at third level), and subsequent travel restructions, all mean that she hasn't been able to travel to Germany since her father died, although she does phoe her elderly mother every night.
What some people have experienced ad endured is absolutely heart-breaking.