Try find the fun in it again. Maybe this looks like going on hacks, spending time with your pony without riding, messing around at the walk bareback, or anything else low-pressure - I know it's easier said than done, but sometimes you need to take the pressure off 100% to remember why you loved it in the first place. It doesn't sound like just forcing yourself to do the scary thing has worked so far, so maybe a different approach is necessary.

100% agree with Kuewi though. Being honest with your trainer will give them the chance to help you with it. That's exactly what they are there for. An outside perspective (especially while riding, as the anxiety rises) is invaluable. Confidence knocks are normal and nothing to be ashamed of - you've got this <3