This is a great question! Thanks for asking!
I was an academic advisor to a gentleman who did exactly what you are asking. He was a double-major in Computer Science and PreMed. It worked for him because:
1. He was really good at being proactive and scheduling his entire curriculum. He worked with both me (his CS advisor) and another advisor in PreMed to figure out what courses he needed to take and how to fit them all in five years.
2. He was really organized and had really great study habits.
3. He acknowledged the big academic challenge and didn't force himself to finish his degree in four years.
But like others point out, this kind of double-major is really intense. Premed and CS have very little overlap in their two curriculums.
If you are interested in Premed, go for it!
If you are interested in CS, consider other fields in which you can develop medical devices or applications for medical practitioners.
There are a lot of ways to marry these two interests other than just a double major. Try to think outside the box. But if you find that the double-major makes the most sense for you, go for it!
I wish you all the luck in the world!