that is stalemate... not checkmate
Checkmate Draw
No, it's checkmate.
Unfortunately, if you actually look at the game:
https://www.chess.com/live/game/3134349716?username=kz872
... you'll find that the server didn't receive your move before your time ran out. Since you were out of time, you couldn't win, but since your opponent had no pieces left, he couldn't win either. So the game was ruled a draw.
whoops. you are right. my bad. insufficient mating material was a painful thread before. hopefully this one doesn't go that route.
[Site "Chess.com iPhone"]
[Date "10/10/2018 07:48PM"]
[White "zeak146 (1740)"]
[Black "kz872 (1698)"]
1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6 4.O-O Nxe4 5.Bxc6 dxc6 6.Nxe5 Bc5 7.Re1 Bxf2 8.Kf1 Bxe1 9.Qxe1 Qf6 10.Nf3 Bg4 11.d3 Bxf3 12.gxf3 Qxf3 13.Kg1 Qf2 14.Qxf2 Nxf2 15.Kxf2 O-O-O 16.Bf4 Rde8 17.Nd2 g5 18.Bxg5 Rhg8 19.Bf4 Re6 20.Bg3 f5 21.Nb1 f4 22.Bxf4 Rf6 23.Kf3 Rgf8 24.Nd2 Rxf4 25.Ke3 Rf2 26.Ne4 Rxc2 27.Rf1 Rxf1 28.Kd4 Rxb2 29.a3 Ra2 30.Kc3 Rxa3 31.Kd4 Ra2 32.Ke3 Rxh2 33.Ng3 Rff2 34.Ne4 Re2 35.Kd4 Rxe4 36.dxe4 Rh4 37.Ke3 Rg4 38.Kf3 Rg6 39.Kf4 a5 40.Kf5 a4 41.e5 a3 42.e6 Rxe6 43.Kxe6 a2 44.Kf7 a1Q 45.Ke6 Qa5 46.Kf6 Qd5 47.Kg7 c5 48.Kxh7 c4 49.Kg6 c3 50.Kf6 c2 51.Ke7 c1Q 52.Ke8 Qe3 53.Kf8 Qf5 54.Kg7 Qg3 55.Kh6 Qfh3# {Game Drawn}