The mathematical version of the question - why am I not losing weight

This topic is probably getting boring, but I am sitting here, wondering what I'm doing wrong, & hoping you all might have tips for me. :-)

Here's the executive summary. I looked up my weight from exactly one month ago, and it's 156.8. Sadly, the exact same weight that I was at this morning. Down to the ounces. So, this of course means that I stayed exactly the same over the course of a month.

Note that I don't plan to track things this anally every month - just trying to get a handle on my lack of progress in February:

• I consumed an average of 1546 calories per day. About 50 calories higher than I normally shoot for.
• I worked out 15 times in February, so just under 4x/week. I did 500+ minutes of cardio, started running, and worked out (IMO) fairly hard.

According to the tools I found online, in order to support my body weight & activity level, I need to consume 2304 calories/day. Given my average daily calories, I should be generating a deficit of 758 calories/day, or what should net out to a 6 lb loss for February. Obviously, this is not the case & I lost nothing. Why? How? I'm SOOOOOOO frustrated.

Here are a few potential reasons I came up with:
-I'm underestimating the amount of calories that I'm consuming
-My metabolism is much slower than the calculator predicts
-The world is against me ;-)

The first option seems the most realistic, but I'm also trying to go by how hungry I feel each night. I would say that my stomach is growling or I'm at least mildly hungry about 95% of the time, so calorie counting aside, I feel like I should be losing weight.

Has anyone else been in this position? Any adivce or tips you could share? The only option I can think of at the moment is cutting back my calories further - possibly to 1300/day? I'm already getting in the best workouts I can on almost every available day, so I don't see much of an opportunity for improvement there.