There are many things can that go wrong. It might just be that you are taking time to learn a new technique, perfectly normal. However, a few weeks after I bought new skates, I tried my old ones and could barely skate, there was something very wrong, it felt as if a blade holder was at the wrong angle. I suspect they were indeed faulty. However, I kept falling backwards in my new skates after one sharpen. After figuring out that the new skates were much too big, and getting proper skates, properly sharpened, my skating improved dramatically. If skates are too big, the balance point can be off, which I think is worse with hockey skates as they are less stable. If your skates are not properly sharpened, the edges will be off which will make life hard. It might also be that your ankles are not so strong, or your skates are not supportive.
It took me a while to learn to glide in a circle on one foot on an inside or outside edge. I had to learn to bend my knees, and use the free leg as a counterbalance with the leg bent, and the knee held in front of my body. It seemed hard at first, but now it is very easy. Edges are incredibly important as they are key to so much skating.