Honestly, 3 weeks is not long. If you don't have a scale, it's kind of hard to say. Normally if you stay consistent long enough, you will keep losing weight as long as you're still entering a calorie deficit. So you will lose weight quickly at first but then taper off. Which is normal. You can try burning more calories or try building more muscle so your basal metabolic rate can increase.
You could increase your calorie intake and then decrease it again, but it won't make any long term differences. Once it's been like 3-6 months of no weight loss then I would be confused and try to look into it, but it's unlikely that this is an issue you'd deal with long term if you stay consistent enough.
It obviously depends on your height, your starting weight, your current weight, how you're tracking your calories, how often you weigh yourself, how much water you consume, what type of nutrition you're having, what's your body fat % starting vs now, and so on. But on the limited information, it sounds like you're fine if you stay consistent enough.