Won a draft and got 8k loss

I was playing draft and it went out good and I won all of the 4 games. So I got a 50k (12 players, 12 gold, 12 rare) pack. All of the players (83 max) of that pack wouldn’t sell in transfer market so I had to quick sell. 

That means I spent 15k, won the draft (4 matches) and got 7/8k back. So I got 8k loss. I really can not imagine how you can even make that possible as a game developer. 

What are your opinions about this?