Hello my friend!
You shouldn't feel guilty for getting things that you want. Enjoy the here and now. Worrying about it too much can lessen your enjoyment of life. Yes, you are sick but that shouldn't stop you from enjoying the blessings that you have. You DESERVE IT! You are allowed to buy things for you. It doesn't have to be extravagant but just enough to enjoy the little pleasures in life. :)Aja!