There is a reason why people say, "When you fall off get right back in the saddle."
I realize you did not FALL off, but all the same, your confidence is shaken.
Have you considered saddling up, getting on and having your husband halter you around the pen/arena/driveway for a bit.
or, even just get on, reins in hand, and don't even walk. Up and off. Depending on your level of anxiety, that may be all you can handle before your tension shoots into the horse.
I'm 46. I took a stupid spill bareback off a Halflinger (not my horse) 2 weeks ago and totally sprained and bruised my leg. I am just barely able to walk without a lurch. And it has made me CRAZY. I fell off that dang pony and after I walked it off a bit, my trainer put me back on that horrible wretched beast, sans saddle, and made me go around several times.
Probably a good thing or I wouldn't go next to the hairy hay burner today.
I have a 15h QH who behaved like a beast on the trails one cool drizzly morning. Loped up hills, slid down hills, a general brat. The entire time I thought this is it. I'm gonna buy it. He is going to fall and then smoosh me under him. I envisioned my mom crying over my casket cussing me out for buying a stupid horse.
I know that fear you speak of. It's based on our age.
Take baby steps. Have someone control the horse from the ground, but schedule time on the horse. Mon/Wed/Friday. Spend more time saddling than you do in the saddle, but at least get it on and get on it.
Everytime Sam loses his footing or stumbles or trips you can hear me gasp across the state of Missouri. But, as soon as he takes 4 more good ones I'm fine.
Good luck. think baby steps.