Some good things feel terrible first. The first walk after surgery is the fair example — down the corridor and back, holding the rail, and it is awful, and it is also precisely the right thing to be doing.
Feeling bad and being bad for you came apart from each other a long time ago. Physiotherapy hurts. Difficult conversations hurt. The body has no reliable alarm for telling the two apart.
So the thing to protect is not your comfort but your reasons. Choose against feeling bad wherever feeling bad buys nothing — and there is a great deal of that going spare.