How to deal with toxicity

Hi. I'm new to overwatch, and my SR is 1919. I hovered around 2100 for a while after being placed, and I am trying to get better at playing soldier because he's the hero I've found I like the most. However, because my winrate is low, (sub-30% over <10 games) people flame me for even picking him. How do I deal with this? In my last game, even though I had gold medals for damage, elims, and objective elims, I was still flamed over voice and text chat.