The FloodReady Website is a network of stream gauges across Lycoming County which helps residents track the water levels in our creeks and river, current rain fall information, and history of flooding at various gauges. This site gives near real time readings and helps residents prepare in the event of flooding.
The half life of doxy is 18-22 h. Since you took four days' worth, you were in steady state. In five half lives 95% of the drug would be eliminated, and in 7 half lives, 99% is eliminated.
The half life of doxycycline is 18 to 22 hours. That means the blood level will drop by one half in that period of time. Forty percent of the dose will be gone in 72 hours. In another 72 hours, 40% of the remaining 40% will be gone, and so on. Some seizure medicines will cause it to be eliminated more quickly.