I have a medical condition that causes me to use the bathroom more often. I usually use the bathroom 4 times in middle of the night. Sometimes from the time I go to sleep until I fall asleep I use the bathroom 3 times. As a result, many times when I say Asher Yatzor "chop plop" just mumbling the words bec. I am very tired. Will it be O.K. if I will say one Asher Yatzor in the morning, and that will cover all the times I used the bathroom in the middle of the night?

Shalom U'vracha, Reciting merely one 'asher yatzar' in the morning would not be sufficient. That is because it would only cover the last time you used the bathroom, and you would not fulfill the requirement to say 'asher yatzar' on the previous nightly occasions you utilized the bathroom (see Mishna Berura (4:3). See also Halichot Shlomo 20:45) I wish you a refuah shlaimah and a chag kosher v'sameach!