Not hungry.

You are probably tired because if you are constantly under your calorie goal then your body is going to go into starvation mode and by the sound of it it sounds as if you are already there. There are lots of ways to get the calories you need. I do mini meals instead of regular meals with the exception of dinner. Try eating 150-200 calories every 2 hrs. During the day I eat lots of veggies, they are basically free but I always eat full fat dip for them just measure it out. I am not trying to tell you what to do it just works for me. If you are working out then you need protein, etc. The idea is to build lean muscle and if you are not eating enough to fuel your body it will store fat. I hope this helps

This is a sample of what I eat and I am 5ft 6 and 157lbs and losing about a pound a week with out trying. This is what I eat on days I work out before work.

Whey protein shake with skim milk ( try throwing a T spoon of peanut butter in it for extra protein and calories
4 stalks of celery, 8 to 10 radishes 6 pero mini sweet peppers with 4 Tablespoons of marzetti dip(that is where I get my calories for that one

orville redenbacker kettle popcorn (yes the whole bag

2 cups of pineapple
banana
a couple pieces of dark chocolate
now i have managed to get in a variety of fruits and veggies
I log everything and know if I need to force myself to eat a little more. This does not have my dinner included just a sample of what I eat before dinner.

Eh, maybe it's just you don't feel like eating, I mean, the last few days your calories have been low, but the week before they were high enough. Maybe look at your nutrition bar graph to see if there's a pattern there? But yeah, you should probably force yourself to eat more if it lasts too long.