Could he be teething? Try some Tylenol.
As far as wanting to nurse and then just playing around, I would try distracting him. When he asks to nurse, you can suggest a toy, a snack, a story, make a funny face, or whatever. Avoid sitting down in places he associates with nursing.
Its easy to feel used and resentful when the kid wants nothing but booby all the time. But remember, with bf or without, kids go through difficult phases when growing up. Phases where you wonder, "who are you and what did you do with my sweet angel?" All that gets us through is patience and perspective - this too shall pass.