Thank you for reaching out to us again and congratulations on gaining an Aufenthaltstitel!
I'm sorry to hear about your situation and can understand that you feel sad. Have you already talked to her about your problems, if possible? Do you have shared custody of your baby? Then you have rights to see and spend time with your child.
I've had a look and my source says that a separation doesn't influence your gained Aufenthaltstitel, if you gained it individually, not through family reunion and your marriage. They still advice you to go to a local support center and talk to someone in person. Here is the website from Flüchtlingsrat Niedersachsen where you can find the closest one (put in the area or city you live in where it says "Region"): https://www.nds-fluerat.org/beratungsstellen/
I hope this helps a bit. Let us know if you have any more questions.
All the best,