I agree - you've got to set limits to keep yourself happy with nursing. How to do that is the tricky part, of course. =) And some of that depends on how verbal/communicative your daughter is.
When dd wanted to switch 20 times (5 seconds per side with lots of wiggles and crazies), I established the rule of "once per side" for each nursing. She quickly learned to settle down and nurse if she really wanted to.
We had problems with her pulling up my shirt, too, because at home I let her, to keep her face uncovered. In public, I just had to have a hand free to hold my shirt down, and if she struggled to pull it up, I just told her it stayed down or we would just nurse later.
It's tricky - I remember being SOOO ready to wean during that stage. But once we had an understanding of the "rules" of nursing, it was much easier. (We're still nursing at 2y4mo.)
Laura, Mom to Julia, 3 years, and expecting #2 in June 2011!