PLEASE, PLEASE, PLEASE get your own lawyer. I know you have limited resources, but you MUST get a lawyer. It is unwise to sign ANYTHING without a lawyer. You may think you can’t afford it, but you can’t afford NOT to have one.
With that said, I don’t believe your separation agreement has to be incorporated into your divorce, BUT I believe it CAN if you choose. That’s why I stress getting a lawyer. If you don’t like the agreement as you signed it, you need help getting it changed. The separation date is technically the day you or he starts living apart regardless of when the papers were signed, unless there was a date on the papers that you signed that was different than the date of actual separation. In that case, you signed an agreement for that date. Not sure if you can argue that.