I’ve lost the ability to fall in love or even feel emotions.?

Severe depression is usually treated with a combination of therapy and medicine. There are healthy lifestyle choices that can help with all kinds of depression. Even with severe depression, healthy lifestyle can contribute to recovery.

I'll show you an answer with lifestyle resources. It mentions the lifestyle program developed at the Univ of Kansas. The U of K program has things that work on your system physically, like bright light therapy and fish oil capsules. Exercise is very good and you don't have to be afraid of it.

Light exercise - as little as 20 min brisk walking a day helps, and you can add to that gradually so long as you don't get carried away with too much exercise, make yourself sick of it and quit.

U of K says that taking your mind off your problems once in a while with things that are fun or interesting is therapy. If nothing seems like fun, look all over. You should be able to find at least one thing, like a favorite movie. If there's a movie you like, watch it once or twice, then look for ones like it, maybe similar story or the same actor. Keep adding to your entertainment supply to give it variety.

The answer also has the book by two psychiatrists who recommend Asian mind-body practices, with an emphasis on yoga breathing, which is used to treat PTSD.

I don't know exactly what their breathing therapy will do for you, but it won't hurt.

Below: PTSD therapy

https://www.youtube.com/watch?v=Uvli7NBUfY4&t=16s

Yes

You sound like you need therapy. What you're describing is a medical condition, so you can try seeing a doctor first. Google "Inability to feel emotions" to learn more.

consider volunteering. when you help others less fortunate than you (there will always be someone), you tend to appreciate the little things more. otherwise, see a therapist.