is it normal?

Is it normal to sometimes miss the way things used to be before baby? My baby is 2 months almost 3 months old and sometimes I can't help but miss the way my life used to be before baby came. I love my baby but there are days when he's super fussy and cranky and I'm exhausted and I don't know what to do. That's when I miss the old days when I just had to worry about myself. 
I'm a FTM so all of this is new to me. 
I've read other articles where they said this feeling could be PP? But I don't always feel like this. Just when I'm really tired and exhausted and baby has been fussy for days/weeks. 
Anyone else sometimes feel like they're just overwhelmed?