informal recruitment after formal rush

Most likely. My first year in my chapter we had to do informal rush and we had to turn girls away. Easiest way to get the list down is to cut off at a certain GPA.

A subpar gpa is a subpar gpa, no matter how you go through recruitment. Sororities aren't going to lower their standards for you, snowflake. Even if your gpa was better, I wouldn't count on an open bid after formal recruitment. There are very few openings and competition is fierce. Study hard and bring your gpa up over the next two semesters. That's the only way you will have even the basics sororities want.

Yeah, you're not going to get a bid with a GPA that prevented you from rushing in the first place. Remember, that GPA was the bare minimum to just rush and a lot of houses require a higher GPA to receive a bid. Informal isn't an easy way out, it's even more competition for a couple of spots.