[Goran]

If your cat has gone get it replaced soon. Mine broke apart and rattled badly, one large honeycomb piece was moving around and partially blocking exhaust flow. Having seen it I wished I replaced it much sooner, must have been like this for almost a year.
Car drives much better now, must have been choking at low rpm. Very noticeable with a clutch.
You don't want exhaust gasses struggling to escape, potentially backing up to the exhaust valves and building up heat.
Hopefully yours has blown straight through removing any obstruction.