Ravenously hungry on maintenance.

I've been on maintenance for a couple of months, I was finding it doable but the last couple of days I've been super hungry, and I find if I don't eat, I get headaches and sometimes feel nauseous. Diary should be open, please feel free to have a look and critique.

2 excellent things.

The BMR that MFP estimated as the foundation to all the math may be wrong, and yours is higher.
Perhaps because of more muscle after your journey, perhaps always higher.
Whatever the reason, that would be great.

One way to get a better idea if the foundation figure is correct or not is go by body composition BMR estimate, which can be much more accurate.
Need your body fat %, doesn't need to be super accurate, because 3% one way or another doesn't effect the figure that much.

Here is a site to estimate if needed. http://www.fat2fitradio.com/tools/cbbf/

Take the bodyfat % figure here - http://www.exrx.net/Calculators/CalRequire.html
Change the height to bodyfat, and see what the BMR is.
Compare to MFP, may be higher estimate.
Even if not much, you may be higher anyway!

Other reason, your maintenance calories are based on your selection of activity level, and you may have selected wrong, so your maintenance estimate should actually be higher.
Or you exercise on regular basis and don't feed the workout, which means your body is hungry for energy, and you aren't providing enough to go around.

That ExRx site also has maintenance estimate calculator you could try hand at.
Just confirm if you workout 3 days a week for 1 hr, that is NOT 1 hr daily avg. that is 1 hr x 3 days / 7 = daily avg.
And reading and TV and movies is Resting.
Others levels are described enough.

So if your BMR ends up being higher, your maintenance will automatically be higher.
And it may be your maintenance calories needs to be higher all on it's own.

That's a great thing, you can eat more and still maintain!

The fact you are hungry hopefully means your metabolism has not just slowed down yet to compensate.