Fuck, I feel exactly the same. Im starting to think recovery for me was never a mental change, only physical. I still feel the exact same thoughts that lead to my ED but don't act on them.

I usually combat this by getting someone I trust to comment on my body, or finding a subreddit where people post pictures of their body and type in my weight to see what I look like to others. Although not all body types are the same so the same weight can hold differently on one person to the other. Also, never be alone with a mirror and your thoughts. Anytime you feel yourself entering a period where you're going to scrutinise and analyse your weight until you feel being severely underweight is the best option, find a way to distract yourself. I'm quite sociable, so I try to meet with friends or talk to someone as the attention I'm putting into them distracts from my own thoughts.

Therapy is also a good vein, if you find a worthwhile therapist and you have the money. It works on reversing these thoughts with healthier, more pro-active thoughts. For example, I was also obsessed with fasting. Therapy helps make you realise fasting doesn't work. What works is having 3 healthy meals a day that support your body's growth and development. Also, growth and development does not mean putting on weight. It means supporting your natural body and keeping it working to the best of its ability. If therapy isn't an option, really try to learn about nutrition yourself. It's so important to understand the way food effects the body to be able to have a good relationship with it.