I want to chime in and say that it does get better. I have been 'alone' for over 2 years now (the age of my DD) and I was pretty much alone during her pregnancy too. She was not planned (but MUCH LOVED) and I knew I wouldn't be with her Dad. I get used to get lonely, sometimes I still do but it's very few and far between. I don't know how old your DC is but maybe you could make special traditions for the two of you and that could curb your lonliness. It's really not so bad
