Thank you for your letter, dated ____________. I was delighted to have a letter from you. I am pleased to learn that you care for me.
I am fine here and keeping good health, though I had a few bouts of sneezing during the last weekend. I was delighted to receive an invitation for the party. However, I would not be able to accompany you to this party. Please do not mind it. I am awfully busy now a day and cannot afford to disturb my schedules. I have to take my mother to the hospital. She has not been keeping good health since the end of the snowfall in ____________ (Place).
She is a patent of asthma. Inhalers no longer work on her and she has to be hospitalised now. My father is away on a tour and would not be back before the middle of ____________ (Month). My brother is a student at Essex and he is also not available. Further, as already explained, I am also having a sneezing problem.
Further, I received a poor B+ grade in my last examinations. I have not been concentrating on my studies since February due to mother’s illness. I am not regular to my college and my trips to the hospital are quite frequent. Further my friend, Penny, had also to be hospitalised as she had a nervous breakdown. I, along with another friend, went to pay her visit and she is feeling better now. I could not have ignored her during her illness. My dear, how could I leave everything midway and join you at the party? I have responsibilities, tight schedules and above all, high level of stress. I do not want to keep you in the dark and that is why, I have explained everything in a nutshell.
I hope you would empathise with me. I assure you that I would not disappoint you in future. But for the time being, please take my best wishes for the party.
I thank you once again for this invitation. Yours loving friend, (Your Name)(Your Address)