Hi there...whatever you do, don't decrease your calories. You're not eating too much at 1840 - probably not eating enough actually, especially if you eat under 1840 and more like 1600-1700 quite often. Can you tell us how long your 8k runs are? Is that 1 hour of running or more? Chances are that 3 lb fluctuation is just from your weekend eating and nothing to be concerned about at all. You'll probably see it leave quickly, so try not to worry about it too much.

I entered your info into Scooby and I actually chose the 5-6 hour activity level for you. I think this might be more appropriate for your activity level since you run quite a bit, which gives you a higher TDEE and calorie allowance. I don't think your exercise quite adds up to 5-6 hours, but you have to remember to also consider your daily activity as well, and for many people, unless they are completely sedentary all day, they already fall into the lightly active category and then exercise pushes them up from there. It's important to count daily activity too! It adds up to way more than we realize and without counting it, we find ourselves undereating by quite a bit. For example, I work out 3-4 times a week for 30 minutes only, but I choose the 3-5 activity level for myself because I'm on my feet quite a bit throughout the day.

If I were you, I would at least eat 1840 daily - try not to go below- and see how your progress is when you make sure to hit that number daily. You could also consider increasing your calories some too if you choose to move up to that next activity level. But I certainly don't believe you need to decrease your calories at all. If you do decide to add an extra day of running, be sure to increase cals. I hope this helps some!

You do realise that weight loss is not linear - some weeks you go up, some down and some stay the same. You may have honestly gained a bit of water weight. What you are looking for are long term trends.

I also agree that your TDEE sounds too low for your workouts - you are younger than I am, just an inch taller, about the same weight and workout more than me and my cut is 1925.

I would agree with the others. It is likely you are underestimating your activity level. I work from home at a desk job, so I thought my TDEE level would be extremely low, even with working out 4-5 days a week. I thought it might be something like 2200 or 2400.

It turns out I am burning at least 2800 calories a day (though I'm almost 90 pounds heavier than you, so that is based on my stats) and as I'm still testing it, it could possibly be more.

So I wouldn't stress too much about that gain, especially after a week of no logging and no exercise. Your body may just have taken on a little temporarily to heal itself during that rest and get back into fighting shape.

Another thing to consider. I drink a glass of wine each night. Tuesday night I added some chocolate along with the wine and ended up having a few more carbs that day. Wednesday, I was up 1.6 pounds. Today it's back down to the same weight I had Tuesday. So that kind of fluctuation is normal in a few days or even a week. It's when you see an overall trend of week to week, month to month, that it's likely a true fat gain.