1994 Chevy Astro Chevy Astro Van Wont Start

We have a chevy astro van. I came home about 2 days ago. And I tryed to start the van and it kept clicking when I tryed to start it and it did it several times but it finally started. Today we went to the doctor and I sat in the car with it running and it died all of a sudden. I turned the key to start it back up and the battery acted like it was dead, along with the clicking sound I informed you about earlyer. I checked the oil and it said it had oil in it. Along with water. I got boosting cables and tryed to boost the van off but it still clicks. The dieing part makes me think its the altinator. But the clicking sounds like the starter. But im confussed about it where it would not fire when I tryed to jump the van off. Please help