The only trouble is your loneliness and from that there is too much inward looking.
Imagine a pacman in your head and when a negative thought comes into your mind envision it gobbling it up 
Keep doing this every time you have any negative thought about yourself or your life.
Next, start as you mean to go on. Remove all junk and stodge from your cupboards and fridge bar your absolute favourite ( you can change it week by week).
Next look at all forms of vegetables, nuts and seeds as your new best friends ( limit fruit).
Eggs are great as are oats, and so is healthy homemade type breads.
Next sign yourself up to a gym for regular classes or order weights on line if you cannot face going in.
Download a good exercise app on your phone and do a short session as soon as you get out of bed and just before you go to sleep.
It can be 1 minute in length just to get the habit going, once you've past 5 days then increase to 2 minutes and so on.
Head to the swimming pool once a week for 1 or 2 lengths only and then increase once you get the habit going.
Borrow a dog if you can or aim for a 5 minute walk weekly and once the habit is formed, increase the time and frequency.
Basically if you start small and form fun, easy to do habits then you can get a sense of achievement which will sustain you and encourage you to do a bit more.
Never forbid yourself anything but try and understand that self sabotage is going to be fighting against you and you need to prepare mentally for that.
Your little pacman and your inner little warriors aided by a sense of achievement will all help you.
Good luck, have fun and let us know how you get on 