You aren’t likely to sustain the same pace of weight loss from the beginning of a diet in the long-term.
IME the first month or so of dieting, whether intermittent fasting, extended fasting or CICO I’ve had encouraging and relatively rapid losses. After the first 2-5 weeks the scale gets stubborn as water loss and fat loss and hormones rebalance. A good sleep is super helpful, but a hiccup in your weight loss is likely to sort itself out over the next couple/few weeks if you stay consistent with your eating.
It sounds like you have your calories dialed in. Have you calculated your TDEE? Does your averaged weight loss match up with your calorie deficit? A lot of the first couple of weeks’ weight loss can be attributed to water weight. You’ll likely experience a whoosh in the next couple of weeks, but the scale is never as linear as we’d like.
I know it’s super discouraging when the scale doesn’t inch down as quickly as you expect, but don’t throw in the towel yet!