I ate perfectly last week, stayed within my macros and worked out 4 times and didn't lose any weight

We don't lose weight (on the bodyweight scale) every week. Fat loss - the thing we really want, right? - can be happening, but hiding behind water retention (or temporarily increased digestive system contents on their way to being waste).

It's 100% normal to seem to stall for a week. What matters is the trend over many weeks. For adult women not yet in menopause, the smart thing is to compare body weight at the same relative point in at least two different cycles (like first day of flow, last day of flow, something like that). Some women only see a new low weight once a month (though that's not the norm) - hormonal water retention can be that weird.

What matters is the trend of weight over many weeks. The first couple weeks to a month on a new routine can be particularly weird. Even after that, the scale will go up and down day to day, but will trend downward over weeks if fat loss is happening.

Patience is usually the right answer. While waiting, this would be a good thing to read, highly recommended:

https://physiqonomics.com/the-weird-and-highly-annoying-world-of-scale-weight-and-fluctuations

Please try to relax. High odds that you're doing just fine, and fat loss is happening. Give it a few weeks at any new routine, so you can see a sensible average result. One week is a drop in the ocean.

Best wishes!

Starvation mode, in the sense of your body storing calories as fat, despite your expending more energy than you eat? Not a thing, because physics has laws. Getting fatigued at too-low calories, so burning fewer calories than you'd expect, because of not enough calories to support energy and health while losing weight? Possible.

ETA: Heh. My comment here was added because of a post that suggested starvation mode was happening to OP. That post has disappeared, presumably deleted at its author's request. I swear I didn't bring up starvation mode unprompted. 🙄😆

If you expect your weight to react exactly in line with your behaviour week to week you are going to drive yourself insane.

I lost fat like clockwork, at a steady rate every single month. It was totally predictable as long as I stuck to my eating routine.

HOWEVER, that's not how it showed up on the scale from week to week. On any given week the scale might be up or down or not change.

In fact, I had a pretty predictable pattern of losing weight for a few weeks, then gaining, then staying the exact same weight for several weeks, and then suddenly losing again, and then repeat.

If I paid attention to the scale week to week, I would have believed that my results were irrational. Why did my diet work one week and not the next???

But wait, didn't I say that I lost fat at a steady rate?

Well yes, the scale may have been all over the place, but when I looked at the data over a 6-12 month timeline, I could actually see that my averaged rate of loss was shockingly consistent.

So I learned to just stay consistent in my eating and not pay much attention to what the scale does from week to week. I only looked at my results in terms of overall trends from month to month.

After a year of this, I weighed every day, but only logged the lowest weight for that month. I did this for a year and the loss pattern was unbelievably obvious, and the line on the graph straight down.

So even though my weight from day to day and week to week was all over the place, as long as I tuned that out and looked at the broader trend, I could see that my fat loss rate was actually completely predictable based on how I was eating. The only time I didn't lose was if I ate more, like around Christmas.

In that time I had what appeared to be "plateaus" that lasted almost 2 months, I had massive gains out of nowhere. I had all of the whacky scale behaviour that makes people doubt that their diet is working.

But I had tons of data and consistent eating to prove that those fluctuations were meaningless. If I ate a deficit, I lost fat in a predictable, linear fashion. I just had to be patient and consistent.

As a result, if I am trying something new with my eating, I give it at least 6 weeks of consistent effort before making any conclusions about how it works for my body.

Remember, fat loss is a slow, and incremental process that happens in the background. But water and poop change your weight drastically from day to day and week to week, so what's happening with your fat gets hidden behind those factors until you have enough data to see the trend in the background.

Don't let water and poop fool you into thinking that a simple calorie deficit "isn't working."

Try being consistent for at least 6 weeks and then draw you conclusions.