I'm no expert on the subject, but I was an exercise science major in my undergraduate studies and can say that your skin sometimes lags behind a bit. Skin is ellastic and before it was stretched from excess body weight (fat accumulated between your skin and your muscles). Now some of that fat is gone and your skin is not stretched as much anymore. It should firm back up with a little time. You've just lost a lot of weight in a short period of time and your body is playing catch up!
Two things you can do to try to speed that up are:
-Make sure you are hydrated- drink water! It is the best thing you can do for your skin. Lotion is a good idea as well. How to tell if you are properly hydrated? Two ways (both dealing with the bathroom) first off- what color is your pee? It should be tinted yellow--- but not actually yellow. If it is yellow drink more water. Also, how often do you have to go? If looking at your pee makes you gag, just count how many times you go to the bathroom to pee in a day. If you only have to go 2-5 times a day (24 hours) you should probably drink more water.
-Start lifting weights- and eat some protein- this will help you gain some muscle weight which will help give you a toned look.
Do these two things and in about 2-3 months you should be able to keep the weight off AND get rid of that loose skin feeling.
Also, thought I don't think this relates to you, most complaints of "loose" skin is actually not loose skin but a bad body composition ratio brought about by crash dieting. Read about it here: http://www.bodyfatguide.com/LooseSkin.htm
To avoid this "Loose skin" the best thing to do is diet and exercise and lose no more than 1kg per week.
(As you have done-- bravo and good luck!)