"25M unsure how to approach situation with 25F girlfriend"

Hey Guys,

I '25M' , have been dating my girlfriend friend '25 F' for 9 years now since we were in high school. We are planning to get married January next year. We are usually intimate quite a few times a week but have not been intimate in 4 weeks now. I thought maybe she is tired working 2 jobs and coming home late so i've not pestered her about it. She started working at a hospital as support staff member about 3months back. She is always excited to go to work their working 3 to 4 7hr shifts