How to get on track after moving alone?

Hi, I am 24F . I used to live with my bestfriends earlier and life happened. So now Im staying alone in 1BHK. Earlier I used to cook healthy meals, used to not snack too much and used to smoke rarely. I have moved alone a month back. since then Im not eating healthy meals and eating much outside and snacking way too much. Being too lazy to go to gym and smoking sometimes and Im concerned that Im getting used to smoke alone. Feels like I may get addicted to smoking cigarettes. How can I get back on track and have some motivation while living alone. Earlier as I used to live with my bestfriends, we used to cook meals together, also motivate each other to do some physical activity