It sounds as if the issue is not flaring enough. Landing a light aircraft flat is a bad thing and will certainly result in losing the nosewheel on a 152 eventually, slightly less of an issue on a 172.
To land you should arrive just above the runway at the correct speed as per POH and then close the throttle and slowly pull back on the column until the aircraft stops flying and touches down. If you have it right the yoke should be pretty much all the way back at that point and the nose fairly high