You don't say what sort of trike that you have. I'm guessing that it's an upright delta (1 wheel in front and 2 in back). As others have suggested, you should try out a "tadpole" recumbent trike. These have double wheels in front and are more stable. They are on the expensive side but perhaps you can find a shop to work with you. I recommend browsing
BentRider Online for additional insight.