who is measuring your blood pressure? 70/30 is extremely low. Get thee to A&E, and get a relative or close friend to go with you. Do it now.
THEN go figure out what's going on with your eating habits. This will take longer. You will need serious support over a long period.
These are quite serious issues you are reporting here.
PS I'm with Randy - 70/30 is low enough to have been dead for weeks. Who's measuring it? Do they really know what they are doing? But the fainting
and the rest all says that, yes, it's low anyway. Get help.
PPS something doesn't add up here. They measure 70/30 - and they let you go home? I suggest seeing your GP and breaking down in tears - really, turn on the waterworks big time, give it big drama - and tell him/her all your fears and beg/insist that you see the right specialist, whoever that is.