AITA for talking rudely to my roommate

So just for context, I share a flat with 3 other flatmates and all are of same age. We work at the same firm.

So, one of them pointed out about how I have been rude to her at two instances and I want an honest advice from you guys.

So, once my roommate (lets call her y) was ill and had cough, cold and fever. I didnt want to sleep next to her, cause I could catch the same. But since other of my roommate had her bf over, they shared one room and me and y had to sleep in one. Before going to bed, I just asked her, do you have fever? To which she said- No but she was coughing and sneezing continously. And I just asked her to maintain distance and try and to cough and sneeze on the other side of bed.

Once I said this, she got annoyed and left the room, making me feel guilty.

Another time, we had a coupon of $500 given by the firm to all new joinees and all of us had one. Mine was expiring soon whereas y had already used it. So, i was planning to order for myself and I communicated the same to her since the morning. She also, wanted to eat out and was okay with ordering with me. I assumed since its my personal coupon, i would be using mine ($250) and she would pay for her own.
However, she thought i would be paying for both of us and use the entire coupon amt i.e. $500
And any extra amount we would split it up.

So in the evening, just before ordering when I was discussing with her, we had a little back and forth, cause I felt it was unfair and I genuinly wanted to use my coupon just for myself. To which, she felt extremely bad and just stopped talking to me. While it made me feel bad as well.

Was I being selfish at these instances or should I have communicated well?