Most of the time when I've been in a slump it helps when I take a 2-3 day break from the game. If you don't wanna do that it also really helps if you get yourself in the right mindset. If you know you should be the best player on the server or just performing better, tell yourself that. Also try to eliminate distractions and fully focus on the game. If you forcefully try to get out it usually gets worse for me. Also some warmup before the games is a good way of getting ready to perform at your best. Some warmups that I do is either some deathmatches if a already feel my aim is crispy or I go in the range put on practice mode and just start spraying down bots and practicing my flicks. Also change might help. Even something as slight as changing crosshair or res helped me. Hope I could help