Back in the day I had built myself a very bad reputation as a dumb, lazy bimbo. But one day I was inspired to change: to do the right thing just for the sake of doing the right thing. I eliminated coffee breaks and busted my butt. I studied hard and delivered on every word I said. Minds didn't change immediately, and many were extremely suspicious; but within a few months people started realizing that they could actually depend on me. I was on track for a promotion--but alas, I quit when I had a baby.
I'm sure you'll earn your respect back if you humbly keep your nose to the grindstone. Be patient and give them time to acclimate.