New Mum, New struggles

Hi, I'm unsure if this is a ranty post or a venty post but I just need to get it off my mind

is it normal to feel so damn lonely after having your first baby? I'm 4m PP and aside from a baby my life is dull and quiet, I use to be so active and had friend groups, going to gigs regularly, hanging out with friends regularly now I'm in the stage of life where no one speaks to me barr my fiancé, if not for him I'd be so incredibly lost at this point, I've been working since I was 17 years old so this no work life is kind of strange but also so incredibly refreshing and it makes me feel abit lost somedays, I miss the old me but I absolutely love this new version of myself as being a mum is something I've always dreamed about and my god my daughter is the most perfect little thing I could ever imagine but man the loneliness is killing me, at the start I had so many people asking about me and baby, then she was born and I feel invisible.

someone please tell me this feeling ends, or if im just being incredibly stupid feeling this way? I'm 26 and feel ridiculous complaining like this to strangers on the internet.

(My apologies for the low mood post)