I know how you feel. I felt that way when I was pregnant with my son and his father was nowhere to be found. Ironically, my boyfriend and I are still together, but I spend most the week with him in Methuen and the rest at my apartment in New Hampshire. When I'm home, it's usually because we've been arguing and I'm always very lonely, at night after my son goes to sleep. I know he needs alone time and time with his friends, but I don't know people in New England anymore, so for me, the alone time is more lonely than it is pleasant.
It's not the same, I know, but I think loneliness is more discomfort with myself than it is a reflection on things that are going on. I don't have any real advice except to reach out to people you care about whenever you can. And I may not be anyone you know, but I know how it goes, and you can email me anytime. I'm a good listener.
I hope you start to feel better soon. Good luck.