Can anyone tell me why it ended as a draw after one one repeated move?

I was black. I’m just confused bc this has happened before where I felt fairly confident in my current position but after doing a repeat move, it suddenly ends in a draw when the game definitely could’ve continued. We both had like 20-30 seconds left in the bullet game too. 

Same position 3 times

It's not the same moves over and over. It's the same position.

Yes, moves 37, 39, 41 result in the same position of all pieces. Might not be as obvious on a physical chessboard but computer software can track it accurately in every game even when the moves repeat after a gap of 10 or 20 moves. That is the advantage of playing online on sites like chess dot com.