You poor thing,
I can only imagine how tired you must be feeling, especially with another one on the way. You will probably get lot of advice from parents, which may or may not help you. I had a similar situation and the only thing I could do was try and exhaust my daughter during the day, but then she still woke up several times during the night - I did not know whether it was night terrors, or being over active during the day, but I do remember being TOTALLY exhausted and at the end of my tether.
My DD was younger than yours, but I think that the only way I eventually sorted it, was to convince my husband ( who was also against getting a sleep consultant), to get the help of a marvellous sleep trainer/parent coach ( sounds silly, but I think my daughter was picking up on my nervous exhaustion and frustration and that was not helping the situation, and my 'parent coach ' was an invaluable source of mentoring and guidance for me during this time.)
What I did was get my sleep trainer to do an hours consultation with myself and my husband and it brought him round to the idea of getting her to help us through the night, so we got her in for a few nights and she totally got my daughter into a great sleep routine. She saved my sanity!!
Am sure she would just have an initial conversation with you if you contact her, she has some really simple quick tips to try and is such a calm and lovely person to work with.
I cannot recommend her highly enough.
Her name is Heidi and she can be contacted via her company The Parent and Baby Coach as well as her email
heidi@theparentandbabycoach.com
Good luck and I wish you all the best
xx