Lemonade hits the loneliness nail of the head when she describes not being able to share the minutiae of her day with someone. The advice to this question is almost always to go out and do things, to join in but that can compound the loneliness when you still come home to an empty house and have no one to talk to about what you have been doing.
Others suggest pets and no doubt it's a friendly welcome when you walk in the door but you can't have a meaningful conversation with a pet.
I find writing a journal helps. Advice given to me when I was widowed and something which I still do to a lesser degree many years later. Initially, I'd write down silly, simple things like "Went to the shop to buy milk." anything really just to prove I was still alive and connecting to the outside world. Then, after the sympathy and daily phone calls from friends faded away, when everyone else had gone back to their normal lives while mine had changed forever, my DH was no longer there to say good morning and goodnight, I stuck with the journal and continue to record my daily activities as my life took on its new shape.
I remember the first time I went to a concert alone, something he and I did a lot together, always discussing what we had seen and heard on the journey home. Now, I would write about it in my journal. Writing became my last activity of the day but also sometimes my first. Sometimes, it's good to freewrite just to get the day started. Thoughts about a dream, thoughts about how one feels, plans for the day. All the things one might say to someone if only they were there.
Some of the best diarists are or were lonely people using their quiet time to compose their thoughts and activities into beautiful prose. I suspect the popularity of blogging has a lot to do with loneliness and the desire to share.