Civic 2000

Background: for the past 2 weeks the car has been a little slow to start up. Saturday i turned the key and heard it slowly die. But my radio and lights still worked. Checked the battery, noticed it was a little low on water so filled it up and tried agian. Nothing. Went to remove the batqtery and noticed bolts on the positive side were corroded so could get it off. Got a jump and went to Walmart to have it checked out and they said the battery was no good. Got a new battery all is good, until a couple of hours later I'm stopped with my foot on the brake and it's starts jerking like it's going to turn off. Air is doing the same. Put the card on park and it kept doing it. Any thoughts on what this could be. Didn't do it before the battery was changed.