Hi and welcome.what you are going through now is not unusual,it is possible to be surrounded by people and still be lonely,sometimes even more so because you become more acutely aware of their absence from a group,and wanting to just stay home and to not bother talking is part of that too.
When my mum died there was no where like this I came here after losing my husband,but there have been times even 11 years on when I miss her intensely.