Sinemet

I've found over the last couple of months my sinemet is not working I'm taking 900 mg that's 7* 125mg /1*250mg cr this is just for my legs walking everything else under control by dbs my walking is not to bad outside but inside only good for 1 hr max .then no matter what combination of sinemet staggering all over place.do you think it's due a new medication any comments