Mental illness before pregnancy

So this is a very serious topic and I would appreciate actual adult conversations instead of any hate or pettiness.

I am 19 and am having my first child. 24 weeks 4 days. It's a little girl and I'm so excited for her although in the beginning I didn't want her at all. It was unplanned but in my eyes a blessing all the same. .

With that being said I am starting to struggle more and more with myself, mainly meaning my mental state. I have been diagnosed with depression, anxiety, ptsd, and schizophrenia. I have received treatment for years and was hospitalized for two years. For the health of my child I have been completely mad free since September and I'm just how starting to struggle.

I keep expecting things to get better and they don't. I just don't know what to do anymore. I was trying to avoid going back on disability but it's the only thing I can do to guarantee a bright future for my baby at this point but it means giving up a lot of things I want in life. My SO doesn't seem to be much help and even though he is two years older than me, acts at least 5 years younger 80% of the time.

Any advice from someone who has dealt with or felt similar things would be really amazing. Thank you and have a blessed evening or day depending on where you are.