Tips for combination feeding

Am

My LO is 7 weeks, I go back to work at 12 weeks. I’ve been pumping but he doesn’t like the bottle with breast milk, however he will take a bottle with formula pretty well. Weird?? Any tips for making the transition? I’ll be working part time so 3 of 5 days I will be home with him in the mornings and every evening, I’d like to keep nursing through the night and on weekends.