1990 Honda Civic Water in the exhaust system

I pulled off the freeway to get gas. As I start the Civic up it idles rough. Steam comes from under the hood underneath the belts and bottom pulley and the tailpipe is now blowing steam. I continued to drive a little bit before stopping. I checked the coolant level: overflow was low. I drove the car until it stopped blowing steam. I then was able to add a total of a pint of coolant in the radiator and overflow. The most recent time I started it Water was running out of a drain hole in the muffler (NO green or funny smells) and steam out of the tailpipe and the idle was fine. Any concerns?