That is normal behavior. However, you need to be checking and regulating the temperatures in the tank. Hot side should be 92-94. I would also recommend using a UTH under the tank instead, of course being regulated by said dimmer (up on the page) or a thermostat. The bp caresheet on this site will tell a lot more about husbandry as well.
Oh, almost forgot: Now that your bp is a more normal size, feed 10-15% of snake's body weight in prey every 5-7 days. If you don't have a scale to check its weight, estimate by choosing prey about as large as the snake in diameter at its widest point.