It's All About The Evidence...
Winning your case in Small Claims court is about who has proven their side of the case. Solid evidence is best to establish your proof.
If the former g/f is suing for rent/utilities/food bills, she will have to prove that she actually paid them. She'll need actual receipts, check copies, credit/debit card statements, along with signed IOU'S from you if she did to cover your share, to support her claim unless she gets you to say she paid them. On the other hand, if YOU have those same evidenciary documents showing YOU paid, not only does she lose her case, but you also bolster your counterclaim against her.
Lots of people toss out the "attorney" card to try and intimidate an opponent into compliance. Don't let that fool you. Her "attorney" probably said that to convince her that her case is "golden" too, all the while collecting his fees. In the end, HE still gets paid.