Have I had a break down?

Sophie

I'm 30 weeks tomorrow, my daughter is 4 and just started school, her behaviour is really hard work and demanding. She is having night terrors too, I'm constantly worrying that something is causing it. Me and my partner are arguing alot about parenting disputes. He isn't her dad but is bringing her up I think he just struggles with it sometimes. I seem to have this huge dread at night for the next day having to try get my daughter out into the car for school as she won't do what I say or listen to me. I missed my train to work this morning and I literally screamed and sobbed inconsolably like the world had ended. I went home and screamed and sobbed for nearly an hour. My daughter came home and screamed the place down because we were making her get her pyjamas on. I just went upstairs to bed (7pm) and sobbed and I haven't got out of bed since, I have this huge guilt that I can't just deal with normal daily stresses like most people.. I wish I was a stronger person and be a better mum.. I can't live like this anymore. I feel like it's affecting my child and even my unborn baby. My partner has no patience and has said he isn't happy anymore with me and my daughter but says he does love us. Do I need help? I used to be on sertraline but went off as I was better for a while ..and wanted ttc also.. was it a mistake? Is it just hormones? I'm no longer sleeping and I am just physically and mentally drained I can't face tomorrow.