A.S.
You are in a tough situation, but you should be proud of yourself or standing up to your jerk of a soon-to-be ex-husband. Hopefully, you will get child support for your daughter and maybe even alimony for you. Usually judges won't be so sympathetic to a cheater. You might also qualify for government benefits without his income, so get in touch with Social Services. That is what they are there for.
As far as the security situation, try to live in a good neighborhood if possible. In OKC there are some areas that are significantly better than others. Get some window alarms and an alarm that is really loud when a door is opened if you don't have a monitored alarm system. I had those when I was living alone, and they really did make me feel better. Also, have you thought about getting dog? They are more work, but it is also nice to have another creature around and it would make things even more secure. If you have room in your life for a dog, Pets and People in Yukon does good work and might be able to match you with the right dog.
If you have family members, make sure you use their help to keep you sane. You need to build in time alone for you. You might be able to join the Y for a reduced price or even free. They offer childcare hours, so maybe you can workout and get a break from your daughter if needed. Churches can also be very helpful, so reach out to one if you aren't already involved.
Good luck and stay strong. Better things are around the bend.