Now that you have know what your BMR (basal metabolic rate) which is the amount of calories that you would need if all you did was sleep all day, and hopefully you figured out how many you need for your activity level.
Now you can move on to your BMI (body mass index) which will give you a weight range that is appropriate for you. The one thing with your BMI is that it doesn't take into account your frame. That is why they give you a range. If you are tiny then you should be on the low end of the range, a bigger frame on the top end of the range, and if you are somewhere in between then that is probably where you should be on the range too.
A quick way to find your frame size is to wrap your hand around your wrist. If your thumb and index finger meet then you are probably a medium frame, if they overlap a small frame and if they don't touch then a large frame. While there are actual measurements that you can take to find this out, the simple way is pretty accurate and easier than trying to find the measuring tape.
Back to your BMI, the range for my height 5'4" is 107 to 145 pounds. Yes that is a big range, but like I said before it takes into account all frame sizes, so you have to think of it that way. Another way to gauge your ideal weight is to go by your height. Start at 5'0" and 100 pounds, for each inch add another 5 pounds. That will give you your ideal weight for a medium framed woman. Which is about 120 pounds for someone who is 5'4".
We are looking to be healthy here not skinny. Skinny really isn't all that attractive if you think about it. Bones are sticking out, clothing hangs off of you. You lose your curves and start to look like a boy. That isn't the goal. The goal is to be fit and healthy with your curves.
Now that you have your recommended calories per day and what your weight should be now is the time to make a plan of how to get to where you want to be. If you need to lose weight to get yourself healthy then there will probably be calorie cutting and exercise added. Getting healthy isn't always fun, it takes a lot of hard work and really you are only going to get out of it what you put into it. So if you aren't going to truly try don't expect results.
Next up: Get moving