1st week of Keto diet

Hello just want to share I did my Frist week of Keto and lost 5.1 pounds.   I felt the symptoms of headache tiredness etc for the first 3-4 days. But I feel great now. I hv much more energy and way less appetite.  However I haven’t use the bathroom for 2 days now.  I normally have a very regular bowl movement , so should I be worried ?  I read that it can happen but I don’t feel constipated .  I drink plenty of water and teas about 3 liters  a day .