Cancer and depression - I've tried to remain upbeat & positive but I think it's finally hit me. I feel so lost and scared. Has anyone felt this way?

I was diagnosed last April with metastatic oesophageal cancer, I underwent 6 rounds of chemotherapy which ended in November it was all positive everything was stable. In January I had a period after not having one for 3 years due to menopause, I had ultrasound and they found a mass on my ovaries, I am having keyhole surgery next week to have them removed. I will also be having more chemotherapy. During this whole process I have tried to reman so positive and upbeat, but this week it seems to have hit me, I haven’t been out the house all week, and cry at anything I am really struggling! My husband is so good and tries to encourage me to do things and get out but at the moment I just feel so lost and scared. 
I just want to hide away