Awesome stuff, Voldreg. 12 months ago I was in pretty much the same spot, I was really disappointed in the way I had let myself put on weight over the school year. I took control of it, though, lost 80 pounds in just over 8 months, and am now at a healthy weight and much happier with my lifestyle. I could go on about what it is specifically I did, but I think it's best if you do the research yourself, as I'm sure you will. I will give two pieces of advice, though.
The first is to disassociate exercise and weight loss. Whether you lose or gain weight is entirely related to how many calories you consume. Exercise can be a tool to help increase your daily energy expenditure, but it's not required. Some people find exercise helps bring their diet into line, others will find that it causes them to reward themselves with food and overeat, so figure out what works for you. The first step I would take, were I in your shoes, or were I to do it myself over again, is to look up a food tracker like My Fitness Pal online, and just get used to rigorously tracking what you're eating every day. You can lose weight eating twinkies if you like, so long as you watch your calories. Whether or not you'll get enough nutrients is something else entirely, but mostly unrelated to weight loss. Anyway, I digress.
The second is, you can do this. Assuming you live somewhere in North America, then weight loss remedies are going to bombard you on every magazine cover and internet blog. Celebrities that lose 10 or 15 pounds will be held up as gods and goddesses who have achieved the impossible. Dr. Oz will reach into his bag of 'weight loss secrets' for his bi-monthy article in a miscellaneous health and wellness magazine. Infomercials will talk about their new herbal pill while overly tanned and oiled models pose for their before and after pictures. Relatives will bemoan their own lack of weight loss success while helping themselves to another serving of dessert. I'm ranting now, but really, it's all crap, mostly people just want you to think it's harder than it is, either because they're trying to sell you something or because they're trying to justify their own lack of success. Assuming you are otherwise healthy, it's really not that hard to lose weight, with a little bit of planning and self discipline. Go look at the progresspics section on reddit if you get discouraged, there are plenty of ordinary people who have lost monumental amounts of weight. Stick with it, and you will be successful. You can do this.