Need some advice for my Sigma gameplay

After not playing for a while, I got back into the game and ended up getting placed in Gold. I kind of feel like I'm not really ready for Gold, as I'm getting called trash quite a bit, and I keep getting diffed by other tanks.

H7VAS6 is the replay code for a PC Gold lobby in which I got utterly destroyed by this enemy Sigma. I think he wanted to prove a point or something, so he disconnected for a bit to let our team get an advantage, and then he logged back on at the end of the game to just decimate me.

I'm just kind of tired of getting called trash and flamed all the time. My name is Ilovepekpek. I think my mechanical skills need a bit of work, to be honest. Could you guys take a look at my gameplay, and tell me what I really need to work on the most?

Thank you so much in advance.