Blood Pressure

Does anyone know anything about blood pressure I know that 120/80 is normal and I have a paper with my monitor that says what is too high but not sure what's too low. My doctor is an idiot and has no concerns about anything what so ever. Even the high ones she says is "perfect" so what do y'all think about these blood pressures and also the heart rates over 100 not sure if that's normal either. (31weeks 1day today and preeclampsia in previous pregnancy)