I'm using the CalorieKing software and it gave me under 1200 "net" calories as my caloric need to lose 1-2 pounds per week. So on the days I exercise, I have a credit and can, if I want, eat up to that amount. It's actually a bit less than 1200 net but can be a bit more gross.
I don't like that intake for you at all.
I using standard measuring but,
What is standard measuring?
Measuring cups? Food scale? Eye balling?
from time to time, I'll guess the amount because I hate to weigh and measure.
There's a bunch of people around here that would scream 'metabolic disease!!!!!111'
But I'll tell you right now from my experience, that bolded part above is where the problem lies.
What's 'from time to time?'
Do you truly stick to your plan 100% of the time?
I'm not suggesting you are doing this... but you'd be amazed how many people I've run into saying they eat 1200 calories every single day. When we get down and dirty, it's true... the food they're tracking is worth approximately 1200 cals. But they're also eating other things. And not accounting for that.
Or they are guessing on their caloric intake a lot more than they realize. And it's been shown time and time again scientifically and empirically that people under-estimate their intakes by a shit ton. One paper specifically showed an under-reporting of 50%. I've seen worse cases personally.
The good thing is you've only been doing this one week. You are just learning. I'd 'tighen up' your approach a bit before you start saying things aren't working.