My situation was quasi-similar - I wound up dropping out of formal rush and joining a local sorority a week later via informal rush. (As a local, they couldn't do formal rush.)
I say go for it! A lot of times, sororities release people who would make good sisters, simply because of numbers. Or you may not have met enough people during the parties. Or you may not have made grades, and you've since pulled up your GPA (I don't recall if this applied in your case, I don't think it did, but it's one reason why a good PNM may be released).
Informal rush is a totally different animal from formal rush. It's more laid back (at least at my school it was) ... you're not standing there thinking "OMG, I have half an hour to make a good impression on these women!" Plus you have the advantage of having had a semester to meet sorority women around campus in a non-rush setting (in class, study groups, clubs, dorm, etc).
Relax, and have fun
(and keep us updated!
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