Don't sweat. Just keep at it. I started out the same way. I could easily make a smooth, arcing cruise over to the left of a trail, transition to toe-side for a smooth arc over to the right side of the trail, and then have to practically stop to go back to heal-side.
I learned with a skier. A rather aggressive skier. Probably before I was ready, he took my to one of the double-blacks at Stowe -- the infamous "front four." It felt like I was about to drop off the roof of a building it was so steep. I spent forever just dropping in because I knew that while I could ride toe-side or heal-side just fine, what would happen when I had to link the turns? Simple...dropped in to the left, toe-side turn, rode to the ride, then fell on my ass. Repeat. Repeat. At least you're sitting on your ass when you go down. Makes it kind of easier to get up again!
Practice. Just practice.