Jess, it is great you are taking steps to get healthy! You want to be around for a long time to see those kids grow up!
However, 900 calories is not enough to keep you healthy. The lowest you should ever go is 1200, and that is really pushing it. At 900 calories you are not getting all the nutrients your body requires and you could end up getting really weak, exhausted, lightheaded, faint and malnutritioned at that!!
You should try eating 5 or 6 times a day, trying to get some protein with most of those meals/snacks. Try and eat 11 almonds during the day, whether all at once as a snack, or distributed over the day...they are a good protein source and have the good fats we need. You can safely eat up to 6 eggs a week, and as many egg whites as you want, so you could have a hard boiled egg most days, or you could make yourself an omlette with one egg and one or two egg whites.
Another trick is to avoid "white" food. White bread, white flour, white rice, white sugar, potatoes, etc. Your body converts those foods into sugar in your body very quickly causing blood sugar spikes and crashes, which will increase your appetite.
Eat veggies to your hearts content (except potatoes!), they are low cal, full of good nutrients and fibre. Eat fruit, but don't overdo the fruit as it is full of natural sugars and carbs. Avoid fruit juices as they aren't filling and don't contain the fibres of real fruit.
Well I think I have given enough advice for one day!! LOL!! Good luck! But please, crank up your calorie intake to 1200 a day minimum!!