Logged my last 7 competitive games. Seems like my team is consistently getting ran over by the enemy team. Is there something to do with the matchmaking or is it just straight bad luck?

I even asked another friend of mine about it and he gave proof that he won 17 games in a row as Rocket on an alt account and got up to Gold within a matter of hours. Meanwhile, I got from Bronze 3 to Bronze 1, then down to Bronze 2 and back to Bronze 1 in the same span of time