I think you might be overthinking this.
It's pretty simple. A good average for figuring maintenance
calories is to take your current bodyweight and multiply it by 14. (Assuming you're moderately active.)
At 134 lbs that means your estimated maintenance
calories would be 1876.
If you wanted to lose weight at a reasonable and safe rate, you'd drop that by about 30%, which would leave you around 1314
calories.
So as long as you're getting somewhere between 1200-1400
calories, you're going to lose weight.
The thing you have ot remember is that the smaller you are, the harder it is to lose weight. It's just simple math.
For you a 30% reduction means you're eating 562 fewer
calories per day.
For me, a 30% reduction means I'm eating 701 fewer
calories per day.
If a
pound of
fat is 3500
calories, then it will take you 6.2 days to lose 1 lbs, and it will take me 4.9 days to lose a
pound. That's just mathematical fact and there's no much you can do about it. The closer I get to my
goal, the harder it will be for me to lose as well.
Eating more protein is good - it means you have a better chance of maintaining lean muscle. I try to get 1g of protein for every
pound of my
goal weight, which means I eat around 130g of protein per day. Don't cut back on that.
Keep in mind also that a month isn't really a plateau. It's just a pause. There are a ton of things that can influence your weight over a month - your period, water weight, changes in exercise, etc.
Just keep doing what you're doing and you'll see loss again. With what you're eating,
starvation adaptation simply doesn't apply.