I simply perfected my burrito form in bed last night

_Maybe I should keep a sleeping bag in my place for emergencies. 👀_

You should have asked last night, I would have given you the same answer. 
You wouldnt have had to freeze then!

Satosora

Thank you very much for all your advice, you’re a life saver! I rather freezed the past days than look into it but yesterday night was too cold haha

Shouldn't my heater work if I can move the valve?

Okay, open it to the max and let it circulate. 
If you have to, open some windows. 
You want to clean your piping out if you can. 
If there is some sediment, it could mean that your heater wont work as efficiently. 
Also air will make it less efficient. 
Let it run at max for an hour or so if you can. 
Dont be frightened if there is gurgling sound. 