A Mulligan and Being Realistic

I ran another race.  Actually, I have run two races since my last post about running. A couple weeks ago, I ran a 5k in Fayetteville and it did not turn out well.  I am not sure what happened, but I have lots of theories.  I felt terrible running that day almost from the very start. I think the main problem is that it was more of a cross country race running on grass, in and out of trees, through mud, etc.  I did not know it would be that way and was not prepared for that. Whatever the reason (or excuse),  my time turned out worse than my previous 5k and that was very frustrating. I knew from training that I was better.  I was so frustrated that I thought about stopping this racing experiment.  After giving it some time,  I decided to take a mulligan on that race and sign up for another race in March just to see if that race really was a fluke or if I was not improving.  My goal in doing this running experiment was to keep improving until I reach my goal and if I am not improving I might as well stop.
So I signed up for another race in March which was today up in Bentonville.  In my delusions of grandeur I had hoped to run around a 21 minute 5k in March.  But I got knocked back down to earth and realized that now that I am in shape, I am not going to see the big improvements in time like I did between my first and second races.  The race today was cold, 37 degrees at race time.  I improved my time which is what I am looking for in the very least from race to race. My time was 22 minutes and 18 seconds.  That is only a 42 second improvement over my last race but it is improvement so I will take it.  I will say that it is getting harder to keep this thing going.  It was kind of exciting at first but now it is starting to wear on me.  There are a lot of days that I have a hard time making myself train. And, it is hard sometimes to keep pushing myself and motivating myself to get better.