I'm hitting a 4-month slump in running

To be honest, the days of feeling super excited before a run passed a long time ago,
but for about a month now, I've been running for the fun of increasing my distance and that refreshing feeling after breaking a heavy sweat.
I used to run 4-5 times a week consistently, but I went on an overseas business trip last week. I thought I'd manage at least 4 times a week if I ran before and after the trip, but I realized I wouldn't have the time.
While I was there, I had some social gatherings after a long time, and since most of my dinners were work-related, I ended up overeating.
As soon as I got back and tried to run, I found 3km harder than my usual 5km pace.
This past weekend, while I was stretching and getting ready to head out, I felt such a strong reluctance to go that I just went back to sleep.
This is the first time this has ever happened to me haha.
Others probably want to run more because the weather is getting better, but even during the peak heat, I was out running 5 days a week lol.
Fortunately, after taking a day off, I started running again for that refreshing feeling, but honestly, it's not as fun as it used to be.
Since the weather is cold, my body doesn't warm up as easily, and during the process of warming up, I find myself thinking, "Ugh, why is this so hard?" which seems to kill my motivation even more. I also wonder if the fun is fading because I've reached my goals of running 5km daily or 7-8km.
I lost 10kg over 3 months, but lately, I've been eating whatever I want, so my motivation is dropping and it's just not fun anymore.