1997 Other Nissan Models car has trouble starting.

I didnt start my car over the weekend and then when I went to go to work monday morning the car wouldnt start. Monday afternoon I was told that I needed water in my battery so we refilled the battery with water and jumped started my car. The car started fine and ideled fine. When I cut the car off for about 15 minutes and tried to restart it, it would not crank again. We jumped the car again and I took it to advanced auto and had the battery, starter and alternator checked. They all checked out fine. Now my engine light is on also. Anyway I drove my car for the rest of the evening with out trouble but then when I went to get in the car tis morning it sounded like it didnt want to start. Finally it turned over. We also set the battery on a charge for about an hour just in case. Anyway after driving it for about an hour this morning I came to work and turned off my car. I immediately tried to start it back up and it almost didnt start. What could be making my car not start?