The Warriors topped the table a few weeks ago but their dip in form led to a fourth-place finish and a tougher route if they want to win silverware.
Franco Smith's men host the Stormers in the quarter-finals on Saturday and lock Cummings said: "We're all trying to stay positive. It's tough because it's easy to think we should change things when a couple of games go wrong, but we've had a really positive season where a lot has gone right for us.
"Not a lot of teams have gone to South Africa and won. It's a very tough thing to do. We're not panicking. We're not looking to change everything we do. We've got a way that we play and that's the way we believe is best to win. We're going to stick to that and stick to who we are."
Cummings played in the 2019 PRO14 final when Warriors lost narrowly to Leinster, as well as last season's Challenge Cup final against Toulon, and believes the team can harness those disappointments.
"It's a funny one because losing that [2019] final hurts a lot but it's still one of my best memories in a Glasgow shirt," he said.
"It was a horrible day, pouring rain, and it didn't quite go our way but we were so close and to see so many Glasgow fans in the stands at the Celtic Park was incredible.
"Experiences like that are massive. We also learned a lot from last year in that Challenge Cup final. We didn't fire a shot and there's a lot that you learn from those moments. We're hoping to apply things that we've learned from that in the next couple of weeks."
Cummings also praised the contribution of Max Williamson and Alex Samuel - two young players who have impressed at lock.
"They're the perfect pairing together because Max does all that hard number four work, he's a bit heavier, a bit more size and gets to that grunt," he added.
"Big Al does more line-out stuff but he's still really good around the pitch and incredibly physical as well.
"They have stepped up this year and there's so much still to come from them. They're going to be a massive part of the squad for the years to come."