Tiff i read your post and just had to reply.
You sould like you are in a very similar situation to which i have just been in and i really understand how you feel right now. Your also due around the same time as me!

DH & i moved interstate 3months ago and up until last week we lived with MIL. It was extremley difficult for me and i found myself getting upset almost every day, so much to the point the midwife at my OB and the hospital were concerned about me being border line depressed.
'Considering your BP has already been high this is an indication things need to change.

Do you talk to you dh much about how you feel? I did in the begining with dh but being that is was his mother (like you) it is harder and it the end i think he thought i was just having a whinge. depending on the relationship your dh has with his mum but can he step in and have a chat to your MIL kindly explaining you and he are perfectly capable of making adult decisions about your baby/ life etc?

In regards to your work, is there a way you can start cutting down your hours?
This might make the worl dof difference, you need to probably work but number one is your and your baby's health.

pregnancy hormones can be cruel, you cannot control them, they come when you least expect it and at the time things may seem like the world is falling apart.

i really feel for you because i know once the tears come they are very hard to stop. But i think you and dh need to sort MIL out now otherwise once baby is here she will probably try to be even more overpowering about what you should do and how you should do it.

I hope you have a better day today