I have been trying to gain endurance to run about five miles a couple times per week. I have started running 1.5 miles daily for a week. The run is as hard to do on the seventh day as it was on the first day. How long will it take for me build up to five or six miles at this point

When in my teens, I used to run 10 in the morning and 10 in the evening everyday for 3 years. Their was a breathing pattern I did of 2 breaths out and 2 breaths in, It was hypnotic. I didn't get tired of running, I stopped because I had other thing to do. I thought I would do my whole life. I don't now, I'm 50, and raising a granddaughter, More fun than running, smetimes. She's great
It can be difficult to stick with at first, It will become addictive.
Besides running, you need to stretch, run backwards and up and down stairs, sprints.
How old are you.
If you want to build endurance for 6 miles(10K)maybe do 2 or 3 miles a day. And then once or twice a week, run 5 or 6.
It actually allows you have more endurance in everything.
It is not a waste of energy. It allows you body to run more efficient. Diet, Sleep, and Habbits will be important
Good luck. You will thank yourself later.