How low is your blood pressure? How's your diet and activities?
You should be worried if your BP is consistently lower than 80/50 mmHg.
You can do a lot of things to get it back to normal range which is between 100-120/60-90 mmHg.
First, examine what you have been eating or drinking. If you're not eating much and not drinking more healthy type of fluids, this can lead to dehydration and low blood volume which can be seen in low blood pressure reading.
Second, think about the activities of daily living. Are you just staying on bed whole day? For as long as your not dizzy, walk...walk...walk...this will help increase blood flow or circulation which is healthy for you and your baby.
I hope this helps.