I totally get why this is stressing you out, because you're getting mixed messages and that's so anxiety-inducing, but honestly the fact that your doctor already checked and said everything is okay is really reassuring. At 23 weeks movements can genuinely be all over the place some days more active, some days quieter, especially depending on your position, what you've eaten, or just baby's sleep cycle, so it's not unusual for things to dip and then pick up again. Since you've already been in and got the all-clear, I'd say just keep doing what your doctor asked (monitoring for any big changes) but try not to stress about the day-to-day ups and downs too much. If you're still feeling really anxious, it might help to ring your PD or clinic just to talk through it again so they can reassure you directly, sometimes hearing it again really helps settle the worry.