How is this a draw?

Hey all. Potential noob question but I was comfortably winning a game, I took all of their pieces. This led to a draw?

It’s put me off continually checking the opposing king as thought maybe this led to the draw. However I’m sure it’s a draw if there is a repeated check 50 times.

I had checked this king maybe 3/4 times and as soon as I took my opponents last pawn it was considered a draw? 

like I say it has put me off my next few games and I’ve blundered them from winning positions because I’m avoiding continually checking. Any pointers?

Picture below..

the yellow movement of my bishop is me capturing their last pawn

Stalemate. His king is not in check but he cannot move it anywhere.