Fatigue!

It's hard to give you ideas without more details. Certainly, the faster the targeted weight loss rate, the more probable it is that fatigue will become a problem.

Generically, when starting a new eating routine, an initial period of feeling hungrier can happen. (Some people experience that, some experience more of a "honeymoon period" where eating lots less feels really good . . . until it doesn't.)

There's some amount of perceived hunger that's (IMO) habit based: If we're used to eating certain amounts of certain foods at certain times of day, it can happen that we'll feel hungrier at usual eating times for a while. (For me, that was fairly mild, and only lasted maybe a couple of weeks, but I'd guess that individuals could vary.)

Some questions:

How long have you been eating at this calorie level? How much weight have you lost in that time period? Actual weight loss is a better gauge of whether a given routine is too aggressive than calorie estimates from MFP, fitness tracker or another so-called calculator, but we need 4-6 weeks of data before we can really see a reliable average loss rate trend.

Is that exercise routine new, or greatly increased? Sudden increases in total exercise load - combination of exercise type, frequency, duration, intensity - can cause a counter-productive fatigue effect. A gradual build is IMO a better idea.

Faster loss stacked on top of new exercise and an otherwise stressful life can be an issue in itself: Stress can cause fatigue, and stress from all sources is cumulative, whether the stresses are physical or psychological.

When you say you're only eating 1/2 to 3/4 of your carb goal, is that because you're spending those calories on extra carbs, or are you eating fewer calories than goal when that happens? Some people are more carb-sensitive than others, and that means that lowballing carbs can cause fatigue for some people, possibly more likely to do that with increased exercise load.

Dragging through the day is counter-productive for weight loss, in that it can subtract daily life calorie burn (because we do less, rest more, potentially in subtle ways). IMO and IME the sweet spot is a calorie level that triggers sensibly moderate weight loss but not fatigue, and a dosage of exercise that's energizing rather than exhausting for the rest of the day (after maybe just a few minutes of "whew" feeling right after the workout).

A common problem is going out hard in pursuit of faster weight loss, but crashing and burning because it just gets too hard. Sometimes a slower weight loss rate can get a person to goal weight in less calendar time than a theoretically fast loss rate that causes deprivation-triggered over-eating, breaks in the action, or even giving up altogether.

Losing any meaningful total amount of weight is a long game, not a quick project with an end date. We need the calorie deficit, but we also need to be able to live with it. As a bonus, focusing on making it easier (instead of faster) can also help a person develop new long-term habits that make it easier to stay at a healthy weight long term.

For myself, I decided I wasn't going to do anything to lose weight that I wasn't willing to continue long term in order to stay at a healthy weight. That's worked out pretty well for me so far: I'm in year 8 of maintaining a healthy weight after about 30 years of overweight/obesity. I'm not saying that's right for everyone, though - no one thing is, because we're all unique individuals.

Best wishes!

If you are feeling low energy it's probably the lack of carbs to support your activity levels.

I've gone hard core low carb a few times and found it simply isn't worth the side effects of the low energy levels, plus it's really hard for me to maintain long term.

More recently I've been focusing on keeping my carbs at 50% and it makes a huge difference with energy and feeling better overall.. You can still eat more carbs in your macros and stay within your calorie goals for each day.

Some other possible sources of low energy might be nutritional deficits from stress. I have been working on eating healthier just to feel better, but was still struggling with low energy. Through bloodwork panels, I found I was deficient in Vitamin D and B-12. I also have chronic anemia (lifelong problem). Since I found this out, my MD suggested I take elevated Vitamin D, iron, and B-12 supplements. That has helped immensely.

If raising your carb levels doesn't help increase your energy each day, see your MD for a Vitamin panel to determine if you have any deficiencies.