I started a part time job about 1 year ago. My son is 8 now. For me, I made sure that I was working when he was in school. Occasionally I take him with me if I need to attend an afternoon meeting or something. (He gets to have extra time on his Kindle when he comes with me...
)
It was an adjustment for him to realize that Mommy had a life beyond taking care of him
. What helped him was taking him with me occasionally so that he got to know my co-workers and boss. Now he has a visual of 'where Mommy is'.
I also make sure that I still spend plenty of other time with him snuggling on the couch, reading out loud to him, playing games, etc... To me this is the most important part. I see lots of kids his age that are really 'on-their-own' to entertain themselves with their friends while the parents wait to get their kids out of their hair. I totally agree that there are definitely times that parents need to do their own things (like work) we just need to remember to spend time with them too.
and good luck with your transition. Sometimes that's the hardest until it really sinks in that -everything is still OK, and you are still there for him-