Going on 26 weeks pregnant

As I was waking up today getting up I started feeling like fainting like if my soul felt to the ground started getting really hot to then having an episode of coldness

Every time I’m laying down my blood pressure drops really low and I can feel it cause as I’m laying down I feel like fainting. This was my reading, which is severe hypertension extremely low blood pressure then i get up and i feel dizzy i wait it out then test again and i seem to fall normal range after a couple of minutes should i tell my ob?