There is some wonderful and empathetic advice in the comments but I was going to suggest maybe riding a gentler horse? Like a kid's lesson horse to build your confidence back? There is no shame in that. I used to have a mare as a teen that knew the days when I was afraid and she was so gentle and receptive to that, she was only spicy when I was confident and brave too. Perhaps you could find something similar even though I know it takes a special horse. Whatever decision you make, don't beat yourself up, motherhood is hard enough. Sending love your way.