Advice

So I am suffering with blacking out and dizziness. I know some dizziness is normal during pregnancy, this is the third pregnancy and the other two were not nearly this bad. I actually passed out the other weekend and went to the ER but they said baby was fine and sent me home. I feel this way multiple times a day and I'm concerned about it. I have floaters and black spots in my vision always bit when I start to feel really bad I start getting tunnel vision and my hearing gets muffled and then I get a terrible headache. My bp has always been around 110/70. I drink plenty of water, I was on IV infusion daily in the beginning because of dehydration so I know that is not the case now because I'm very aware of not getting dehydrated. Just curious if anyone else is having or has had this before?