Your sis sounds bloody rude izzy you should tell her to shut up. Seriously. Yes you are lucky to have family to help but no-one should make you feel bad about it and there are different levels of colds. Some are just sniffles and some feel almost as bad as flu, and if you're down and stressed like you have been this last year then you will feel it even more.
Is she at your home? At your mum's? Why is she talking to you so much?
I have to admit that I used to be very unsympathetic (but secretly) to people complaining about colds
and I think it was because I only very rarely got them back then and when I did I shook them off. Then in the last three years they have been horrendous. So maybe she just doesn't get it? No excuse though for being a twat.
My ex was even worse. I was properly ill twice with him. The first time was with glandular fever and he was convinced I was lying and just being lazy, and shouted at me the entire time he was in the hosue to get out of bed and do something. The second time was with flu, proper flu, I thought I was dying type flu. I stayed home from work and he got back one day and laid into me for not going to see his mum in hospital, a 40 minute train ride away on a cancer ward full of people who were immuno compromised. After two days of bullying I ended up dragging myself in just to shut him up.
SO I have been both the unsympathetic and the victim of lack of sympathy and having been a twat who was never told she was a twat and having been the victim of a twat who I never told was a twat I advie you to tell your sister to shut up and stop being a twat.
Wow I get ranty when I am on my laptop with a proper keyboard.