I SUCK at this game

I've been playing Rainbow Six for several weeks, I'm already level 43 but I still feel like a burden to my team. I've never felt this bad at a video game before. I can't memorize the maps, my aim is completely inconsistent, and when someone gives a callout I have no idea what location they're talking about, when I hear footsteps, I have absolutely no idea where they're coming from.

When defending, I just position myself at some random doorway and place my gadgets wherever seems most convenient. I almost always end up with 0 kills and 0 assists, and if I'm lucky, maybe 3 kills.

When attacking, I always end up getting killed even after droning rooms, and I have the worst luck — I breach right when there's an enemy nearby. I'm worse as an attacker than as a defender. I just feel like I hold the team back.

HOW can I improve?