I had something similar happen 3 years ago - I was rounding 3rd base and heard a pop and it felt like I'd been punched in the leg. But mine was in the calf, not the hamstring. The part I'd be concerned about was the pop you heard. It may be a more serious pull that may be 2 weeks or so before you can start getting back to normal, not just a couple of days. With mine, I had trouble walking for 5 days and had a limp for over a week and a half. Like the others have said, stretch, take it easy, not too hard, ease back into it. It will heal, but it may be a bit longer than you'd like or hope.

One other discovery I made - biking muscles and running muscles are not the same muscles.