"Also I am have insane trouble controlling my weight, I am yet to find a safe place to exercise for free (I don't have money to pay a gym), and even with a carefully controlled diet my weight swings around madly (I managed to get 2kg lighter in 4 days, and then 4kg heavier in 2 days for example...) " I've good news about that. The +/- 4kg oscillations are just water, but you can fix the weight problem even without ex…
This is completely true.
I was a D1 athlete through college. Once I graduated and stopped playing, my weight went through the roof. I went from 160lbs to almost 190lbs. I started having back problems and my doctor said I already had some arthritis in my back from both hockey and soccer. I was having a lot of back pain in the morning and during the day.
The doctor told straight up to lose some weight and change my diet. He said taking the additional weight off well help my back a lot; even a few pounds will make a huge difference.
I changed my diet, started doing yoga and stretching before and after my hockey games. Within a few weeks I could tell a huge difference, even though it took me a few more months to get back to around 170. The loss of the weight and stretching made a HUGE difference.