Doxycycline got me constipated. will i start pooping regular when the medication is out of my system? been 4 days not taking it and i poop very little

It's not the doxy: There are other, more common, causes of constipation - so something else I think is to blame. Besides, doxycycline has a relatively short half-life (that's why you have to take it TWICE a day)...so after 4 days it should be out of your system. I recommend increasing fluid intake-such that your urine becomes clear/light yellow. FIBER in the form of fruits and veggies will help. AVOID low fiber food