I agree with the Matt and BN. The tree is trying to go dormant do to the short days and low light of winter but the warm house temperatures are forcing it to put out new buds. This condition will eventually [maybe quickly] deplete the root reserves and kill your tree.

In my experience 2-3 years are about all they can take without going through a dormancy and a needed rest. They;ll do even better growing them outside with a annual dormancy. Since it's winter already I think I would put them in a unheated building or garage and try to keep them just above freezing. There should be time left to give themt a short dormancy before spring comes. Put them outside in the spring and let them grow without pruning to regain their strength.

Tony