Those feelings are totally normal. I went back to full-time work when my now 2 year old was only 4.5 months. I was worried I'd miss out on things because I was working 38 hours a week but I didn't miss out on anything luckily. I was there for her first steps, I heard her first words and all the other firsts.

DH and I both work 38-45 hours a week but we make sure we spend quality time with DD because we can't spend quantity time. After all, quality is better than quantity.

For me I find it very easy to separate myself from work me and mum/wife me. I use my trip between daycare & work to transition to work mode and visa-versa between work & daycare at the end of the day.

I wish you all the best as you start the next phase of your life.