I can relate a lot to what you're describing. A few years ago my heart was aching a lot and I felt very alone although I wasn't physically alone. What helped me was to write about my feelings and thoughts on forums such as this to get support, and connecting to people made me feel less lonely. If you have someone that you trust in reality, you could talk to that person (when I've had people I've trusted in reality that I've talked to I've felt better afterwards).