Honestly, get back on that mare. Try groundwork before you sell her, she could teach you a lot! I was a beginer when I got my two ponies, and they were pretty green. My gelding, Phillip, has anxiety; he's a spooker. And Savannah is a rotten mare, bucks, rears, bolts, kicks.. The works. Savannah and Phillipo, just in a year and a few months, have taught me so much. I'm pretty much breaking young hunter A circut ponies now, because Savannah taughyt me how to ride out rears and bucks, Phillipo taught me how to de-spook. Both have taught me paitents, and to get back on. Phillip spooked & almost broke my neck.. Well, actually it was my fault, I threw myself off.. But right after (I landed on my face, almost broke my nose, bent my neck, and threw my back out of line.) I got back on and trotted, and cantered I'm pretty sure. You're supposed to get back up & ride everytime, even if you're scared.
Good luck with whatever you do, though. :)