Slumps happen. They're no fun. They test your resolve to improve as much as anything.
Ever find yourself in a slump with the game of chess? I'm in that 1600± place (sometimes closer to 1700, sometimes closer to 1500), and for the life of me, I find myself in slumps for as long as 1-2 days. Then boom! Out of the slump, and a few points higher.
All I can advise from what wisdom (if any) gained is, stay with it. Keep on top of the openings. Practice the tacticals. Play hundreds of games.
Thankfully, slumps happen and go.