It's hard. I'm the youngest of 5 children and when my next older brother went to college and I was "alone" at home (and I didn't get on/talk well with my stepmother) it was very very hard. I retreated. If I could do it all again I would think of a project (could be something as simple as starting a journal) and then get out of the house to work on it (go shopping for the "right" notebook/pen, whatever). I'd decide to learn a craft or learn to cook, take a course, etc. and use whatever to help me get my mind off the harder parts of "being alone" until some time had passed and things had normalized/routinized a bit. By then, hopefully, I'd be progressing in whatever I had decided to learn, would have gone to bookstores/library/school for instruction and maybe met someone or gotten additional ideas (learned of a group to join of people with similar interests) and would feel a bit better.