Blood pressure and dehydration

Hey guys. I’ve already had to go to the hospital twice during this pregnancy and I’m 9 weeks. The last time my blood pressure caused me to almost pass out. When I started to feel ok my blood pressure was 90/45

Well today I feel like I’m starting to feel a bit dehydrated again. I drank 73 oz of water plus 2 non water drinks (tea/lemonade mix) so I don’t get why I feel this way. I took my blood pressure because I felt off, almost like my heart was pushing hard with each thud. It was 136/93 a usual blood pressure for me is 110-120/60-70

I guess what my question is, is why is my body acting dehydrated even though I’m getting fluids? I’m not in the sun, I’ve been pretty sedentary due to being laid off.

My other question is my blood pressure has been all over the place. But it’s generally the bottom number that is all over the place when I feel off. I’ve noticed it since the pregnancy started and the only thing that has changed is my eating habits (I was doing weight watchers for 2 years and now have been only able to get carbs down) so therefore I have put on 15 pounds somehow 🤷🏼‍♀️ in the past 4 weeks. The only other thing I can think of is dehydration yet I’m drinking water 🤷🏼‍♀️