Thank you for your query at DoctorSpring.com
I understand your concern.
Metabolism generally keeps slowing down with age, however if you switch over from a sedentary lifestyle to an more active lifestyle it does increase at times. So for example, you had a very sedentary lifestyle, you change that and start brisk walking/ jogging daily. It does impact your metabolism, and definitely improves compared to what it was before.
You're suffering from constipation, which can happen due to a change in diet, excessive protein consumption, lack of water, e.t.c
Since you did not have a BM since thursday it might cause some discomfort. You can try taking bananas, as they naturally improve the digestion as well as peristalsis, helping in bowel movement.
Or else you can try Lactulose syrup 20 ml at bed time, and that will help in clearing the stool.
Feel free to discuss further,