Definitly join a gym. And when u do, remember that nothing happends overnight.
You will get fast results, but you wont get results by the hour.
The most important thing is to keep up your head and continue to go, even tho you will feel tired and urgent to quit. U need to suck it up and go. I promise it will be the best thing that ever happend to you if you just stick it out for the first weeks.
Its a mental game, if you can believe it, you will achieve it.