Hi I am 21 yrs old and 15 weeks pregnant.In the past week I have felt tearing sensations in my abdomen.At one point mild cramps... no bleeding or anything and no more cramps . But is this normal??

Sometimes you will notice some stretching or pulling that can be quite uncomfortable at times as the ligaments that support the uterus stretch. It may have been due to this. By any chance did you notice it more when you moved about or changed position?
Certainly anytime something causes you concern, it is worth a phone call to your doctor or midwife. They won't mind at all and would much rather you call for the peace of mind.