You lost on time, but insted to lose, the match is drawn because your opponent doesn't have enough material to mate you.
Can sound a bit strange, but those are the actual chess rules: If you are out of time, but your opponent dont have the material to checkmate you, then its decalred draw.
I would guess that you ran out of time. Where a player, who has insufficient material left to checkmate his opponent, still has time left on his clock, but his opponent, who has enough material to win, runs out of time, the game is declared a draw.
Actually, you're lucky to receive a draw. If the opponent had even a single pawn, you would have lost on time.
