Low blood pressure and swelling.

So I dont have high blood pressure and swelling which is usually an issue but my low blood pressure has been kicking my ass. I have 3 other kids and I'm pregnant with my 4th, I have been swelling up for 2 months now and now my blood pressure keeps dropping and I feel like I'm dying and I can't even get up. My feet and ankles hurt so bad I can barely walk anymore and I've been having low blood pressure attacks at least 3 times a day which is awful. I hate it I have no energy anymore, I feel as if I'm going to fall out, everything that comes with it... I need help salt helps with low blood pressure but makes swelling worse and vice versa. I'm screwed I feel.... i dont know what to do i called my doctor today waiting on a call back either today or tomorrow. So I don't know...