Had an appendectomy 2 months ago, pain again though.?

I've lifted hay bales a few days ago and rearranged a room including filing cabinets and other heavy furniture. I figured since it has been 2 months I would be ok. But today I'm hurting pretty bad, about as bad as when I had appendicitis. and if I sit down or hunker over it's not so bad. Is it just me healing or should I see the doc?