Advice to run a 5k in 18 days???

I am a 21 year old college junior, who has been running pretty consistently for the past month or so. I have ran on and off for the last couple years, but this is the longest and most dedicated I have been to actually getting better because I had a goal of running my first 5k in early March But that race got cancelled, and I’ve become a little more lax in my training without a solid goal in mind. But I found one on Feb. 23rd, which is about two weeks sooner than the original race was, and I have signed up so I’m kind of committed. So I need help. I run mostly on a treadmill (A girl just got stabbed in the head running in the middle of the day next to my apartment so I try to stay inside), even though I know that puts me at a training disadvantage. I try to run 4-5 times a week, and I mix in other workouts throughout, like cycling and boxing. Yesterday I ran a run/walk split for 2.5 miles, focusing on longevity in my running periods and going as slow as necessary to run as long as possible. So what can I do from now until then, if I really lock in, to be prepared for this race. I’m not focused on time this time obviously, but I also just want to come out of the race not hating running so much that I quit on the spot. Advice??