Dating a doctor/resident?

Hey, advice please!

I started talking to a guy a couple of months ago - he's a doctor 3 years into his 5 year residency at the hospital and also studying for a phd. We had a couple of phonecalls, then he text most days before we met in person a couple of weeks ago. The date went really well - however he's now not contacting as much, and can take days to reply.. but when he does reach out.. the messages are really warm. Can any doctors, or women with doctors let me know if it is a busy thing (I get the role is demanding) or if he just not that interested? Any advice is appreciated, thank you! X