How to lose weight and get back into shape?

As of now I'm 14 years old 140 lbs and I'm at least 5'3. I have not been a big kid all my life, I'm actually not BIG but I'm getting there. Anyways I started a really serious habit of playing Minecraft, Cs: go, Dota 2 for 16 hours a day (about a year ago). Every day, also I've had a concussion recently (6 months ago) So I have not had any physical activity since then to this day. I'm a shy kid even around my family and I'm embarrassed to say to my mom that I'm tubby and want to lose weight because everyone thinks I'm skinny like I have been most of my life. But I'm at the point where if I run up a set of 12 stairs I start to feel out of breath like I just ran a 5k. With no access to gym equipment (I'm also going through financial troubles) besides a treadmill 5-20lbs weights. Not only am I doing exercise to lose weight but to get another habit into my life because I've stopped doing homework and I'm rushing to do it at lunch, in homeroom and many other places. I've started planning this now because it's Summer and I'm finding out now that my grandmother signed me up for soccer (my favorite sport) that I'm really good at but I'm just not in shape to even run a lap around the track. I just need some easy diet, sleep, and exercise routines. I don't want to be ripped though, only toned and get rid of my new born moobs and gut.