I played early with friends, stayed in the 40s, then started afternoon solo queuing and immediately dropped from 44 to 34 in like 2 days of nonstop steamroll games. I proceeded to be stuck in the mid-to-high 30s forever because I stubbornly refused to play with friends thinking they would get less SR for playing with a low rank like me.
I cannot stress enough: the games in the 30s are like playing a completely different game from games in even the mid-40s. Team comps are terrible, offense ALWAYS trickles in....it often seems like offense only get past initial choke points if 2-3 people happen to randomly use their Ults together since nobody communicates. There is also an enormous skill gap since Blizz stuck everyone bad in the 30s after placements, so in like 4 out of 5 games your individual contribution really doesnt seem to matter (you either stomp or get stomped).
It is also VERY hard to tell how you are doing if say you are forced to trickle in with 1 other guy to a 6 person death squad after each death because nobody waits or listens to your pleas to hold on and group up for a coordinated push.
Once I started playing with a team of people between like 44-52, my stats all skyrocketed and the games just got better and better.