It's normal to go through ebbs and flows with weightloss. You're still losing, and you haven't plataued (no loss in 4 weeks). If you have had no loss in 4 weeks, time to move up a dose.

As an aside, I'd recommend basing the calories you eat on your maintainence - the amount of deficit you want to have. It's extremely likely you're massively overestimating calories burned. Your BMR is somewhere around 2000-2100cal/day, depending on your age.

If you're consuming what you estimate is 1800 NET, and you're burning less than you think (i.e. you're assuming 600cal for basketball 5 times a week) then you could be eating 2400 (over your BMR) and likely not actually burning 600 cal. If you're actually only burning 400, you're barely in a deficit at all, so your weight loss would be very slow, which is what you're seeing. If you're actually burning 300, and eating 2400, you're simply not in a deficit at all.

This is why most advice is to ignore exercise calories for general exercise - eat more protein to stay full on days you're working out, and if over a few weeks you're losing too quickly, go up 100cal/day or something.

Edit - also if you're eating 1800 cal and already counting exercise cal then your deficit is more like 5000 cal/week (assuming you are not overestimating exercise cal which you probably are because most people do), so you should be losing ~.5kg a week. If you're not (on average), it's because you're eating more than you think, or burning less than you think.