Feeling constantly bored, no passion in life

(english is not my first language)

Sorry for the long story.

I would like to share what's on my mind, because I feel like nobody I know is able to truely understand how I feel, and how difficult it is for me.

I am in a burn-out at the moment, caused by some medical issues which my doctors don't have a solution for. I have not been able to work more than 2 days a week since I'm 18 or something (now 22), because I am exhausted really easily.

But that is not who I am at all. When I was younger, 15 years or something, I could do anything. Go to school 5 days a week, sport 2 times, work 3 evenings and after that go to the bar with friends. I was always busy and loved it.

Since I stopped working 5 months ago, I have been sitting at home, and at the beginning that was fine because I really needed some rest.

But now I have the energy to do things, but not the mental ability to do so. If I hang out with friends all day, or go sport or something, I will feel horrible the next 3 days after it.
Travelling is also not an option for me right now.

I feel like I really have no purpose in life, and I'm not passionate about anything at all. I have a nice boyfriend, but when he is here for a few days, routine will kick in and we're both just scrolling the internet, which is fine for him, but I feel like I have seen it all, and want to actually do something. But we have very different interests.

The only thing I really like is taking care of my pets, at the moment I have 2 terrariums with lizards, and I like being busy with it. Building terrariums. Building small eco systems for them with cleaning crew insects and live plants and all that. Also I will get 2 new young cats next week so hopefully they will give me more to do and be happy about. But waiting a week feels like ages.

I've always liked to take care of things and animals. Sometimes I just went for a walk of 2 hours because my bearded dragons like to eat dandelions, haha.

But after 10 minutes of my day I'm done with it and there is nothing left to do. My house is cleaner than ever, I eat healthy, everything is as it should be.

Originally I make 3D models and graphics, but now that takes way too much concentration. So I fill my terribly long days with scrolling facebook, watching series, sometimes I just sit here.. doing nothing at all.

I have tried drawing, cooking, and all that stuff, but everything feels so boring, and just not enough for me. I wish I had something I was passionate about, I often just order stuff online, which I don't really need, just to have something to look forward to.

Some days I feel like I want to have kids already, so I have a life goal. Something to live for.

Every day feels like a week, and weeks like months. But when I look back on a month, it feels like it didn't happen at all, just so empty.

I am not really unhappy, sometimes I am, but mostly empty, bored, purposeless
Mostly hating myself for wasting my time so much with doing nothing that I love.

I wish I had a real hobby to be passionate over, but everything I tried bored me after a week or something. My house is filled with paint stuff, guitars, never finished scarfs, and all that sort of stuff... (and I can't keep on building terrariums and buying weird animals, it's expencive and my house will become a zoo haha.)

Maybe someone has some advice for me, good ideas, or just motivating words..

Thank you for reading my story written in my best english.