Bleh I can't imagine how rough it is to gain weight easily, and the constant struggle to keep it.
No, I don't have the same problem but with a brother who for a while really focussed on losing weight and a sister that is trained in healthy food and training I see quite a bit of what would be better for me. My own choice at the moment to do nothing with it, but I will in the future. I was working on my body actively for two years before though. And will start again when I start with hormones.
The thing which you shouldn't do is to try to lose everything at once. Even if you decide to just almost stop eating for months, you will train your body to, whenever you do eat, to safe as much as possible and thus gain weight.
Exercises you can also do at home. Luxury of being a woman is that you don't have to do 100 kind of exercises for a good body. Just work on your stomach and all around that and you will get very far already.
If you look at these:
http://www.buzzfeed.com/ailbhemalone/workouts-that-you-can-easily-do-at-home1,6 and 11 are good ones.
I can't find it but I recall someone giving exercises you can do while on the sofa, watching tv and in between breaks. In case you can't get yourself to work out you just have to remind yourself that whenever your tv show is on a break, you can train then.
Also if like me you are lazy and just often can't get yourself to work out.. punish yourself for it. When I worked out I told myself I could have my favorite snack (bag of chocolate thingies

) once every week (I did go to the gym three a four times a week). If I skipped a workout, no chocolate for me.
You don't have to stop eating what you like but just eat.. a little less? Instead of taking a big breakfast and dinner it does work to take a small breakfast. You will get hungry with a few hours again. Try to take a simple snack. Fruit would be perfect and with dinner just keep it simple.
Also the biggest change I saw my brother do; drink water. When you get hungry at times, drink. Instead of limonade, juices, anything, drink water. He lost so much weight when he did just that. He ate as he always did, he didn't exercise, he drank water. And lost weight.
Losing weight and/or improving your body isn't about putting your mind to it for a certain time (although that is also a possibility but just harder to achieve and hold on to) but a lifestyle. If you want to lose weight you do need to change your lifestyle and take things slow. But it will get better ^^. Just push yourself to take things slow, don't force it and enjoy it if you lose 1 kilo or whatever you got over there

. You rather see it go down than going up even when it goes slow. Do weight yourself at the same times though. If I recall it correctly you weigh less in the morning.