Advise pls

I'm so deeply sad/ depress, emotional, broken how can I stay strong for my daugther? I have a 2 year old, she speak very clear for her age and understant more them anyone thinks. She has ask me today "are you okay mommy"? Why you sad? This just break me even more. As she hug me she say I love you mommy. I don't know how to get out of this, how can I just be strong, seeing my daugther just break me bc I can't just give her what I didn't have as a child. I just need to vent sorry, I have no one to talk about this. 

So we are currently 33 week with our 2nd child and maybe is just my hormones but I'm having all type of mix feeling about my So at this moment. I feel unhappy, I don't know if I trust him or if I can trust him anymore in the past I cought him talking to his ex but they just talk but IDK if I should just move on and stay away from him now. He has been great this past couple months but I don't know. I don't go on his phone or anything as I'm trying to be in peace however today He let me use his work PC as mine is not working and as I open it some chat between him and his coworker was just sitting the and I read that he might be moving out after our son is born etc so I did not continue to read anything else. What do yall think? What should I do? How can I stay strong for my kids? I have no family member in the USA and We both own our house. Any helpful advise?