Beginner here, can someone please explain why this match ended in a draw?

New to chess here. This game ended in a draw and I am confused why.

I am black

I am ahead on time, and i am ahead with a queen, two castles, two bishops and 3 pawns.

I am not too concerned about not getting the win, just confused on why the game ended. I was quite certain i would win but it just became a draw. Neither player offered to draw 

This game ended in stalemate when a player on their turn has no legal moves, and are not in check it is considered stalemate. Stalemates are considered draws in chess.

Your opponent had no legal moves but wasn't in check and it was his turn, so it was stalemate.

You had 5 different checkmates - 41...Qae2#, ...Qag2#, ...Qxc4#, ...Qf3# and ...f5#.

Next time, DON'T promote so many Pawns that the opponent runs out of moves and draws by Stalemate. Just checkmate him instead of trying to torture him.

In a situation like this always check what your opponent will/can play next. If there is no legal move, then you have a problem

It is because of stalemate. A good tip I've told some beginners is don't ever promote to many pawns, or if you do need to promote more than one, promote to a rook. Queens control too much and in an endgame like that it is incredibly easy to accidentally stalemate. You also had five or six checkmating moves there- it might help to try and scope out the board before each move to look for opportunities.

If it is your opponent's turn to move, he has no legal moves and he is not in check, the game is a draw. Such situation is called stalemate.

Oh I get it now. Wasn't sure what a stalemate was, now I know. Thanks for the tips guys. 

Your practical advice is not good. A better advice would be to think before each move. Another good advice is to learn the most basic rules (like stalemate).

But this is all moot. Davidkimchi is a troll, don't take him seriously.

Got another stalemate. I changed the last pawn into a rook like the other person suggested, but still find it hard to checkmate

If you didn't have the extra Queen on d6 (or, alternatively, the extra Rook on c5) then there would be no Stalemate.

Try just promoting ONE extra Pawn.

That's overkill

When you have so much extra material (overkill as @ScatteredWealth phrased it), it is sometimes tricky to avoid stalemate because there is so much to keep track of. Here are two beginner-friendly videos which should help (intermediate and advanced players might benefit from one or two things in these videos too)

p.s. Winning with even just an extra pawn (first video) takes more precision, but knowing how to do this consistently should also boost your endgame confidence a lot. As for the Queen checkmate (second video), the first half of the video summarizes how to give a Queen checkmate (one Queen) and then towards the end, I "improve" on this subject and display how to quickly checkmate.

I'm going to post a play on how to always win with checkmate with nothing but a king and rook, because that is all you need and for you, it would be safest.

Please note that there are many quicker ways to mate w/ king + rook, but that is the safest. As a general rule I never promote more than two major pieces, if I still promote I underpromote.

Just try to memorize the pattern, and you're good to go. Good luck!

Thanks. So backing them into a corner works safely

As long as you never take away their LAST flight square until the move that mates.