I feel like my teeth are about to fall out, what do I do? (Photo)

Prior to what I'm currently going through, I was going through a rough depressive state, and I stopped brushing my teeth for 2 months. I'm a smoker, so that makes it worse. My teeth are chipped, and I can see inside my teeth. I'm not having any pain, which is confusing me. I made the habit of not brushing my teeth as a kid, and now I regret that decision. I've been brushing my teeth as much as I can, but nothing is working. I need help asap. Some teeth feel mobile, but I'm not sure if they're loose.