Feeling alone and sad

Am I depressed or is there something else wrong with me?
I am 23 years old, married, and have a 7 year old and a 4 year old. I have been with my husband for almost 9 years, he was my first, my last, my only.
I think my troubles start with him. No matter what I do, where I go, or who I talk to - my husband always has something negative to say about the situation (by the way he is about 12 years older than me). He will accuse me of cheating, wanting to cheat, or trying to leave him and its driving me CRAZY!!!! He just wont give it up...
Now, I am currently in University and starting to struggle with keeping organized, keeping up with the work load, and look after my family - I am also afraid that university maybe wasnt the right thing for me - but I keep going to show my children they need to go to school if they want to succeed in life, I have always believed education is essential, but am I doing the right thing? My husband also has negative things to say about what I am taking in school - social work. He can never seem to be happy for me....
This past week I had two job interviews related to my "field" of education - and now I am afraid that I wont get the jobs and then my husband will say, "i told you so" - more negativity that I dont need, I wonder if applying for these jobs was even worth all the troubles it will bring (whether i get them or not)...
I am also feeling very sad lately, like there is no where for me to go - no one for me to talk to; I feel this way because I know that I have done this before and anyone who I can talk to has heard my crap already and is probably really sick of it....But I just need to talk through this, someones advice maybe - I feel so lost and dont know what to do!!!!!