You need a 4 year degree for piloting, it is a check the box sort of thing, so by all means continue in your chemistry or premed education.

In the meantime, continue flight training on your own dime as a hobby. I obtained an engineering degree, and in my spare time got my private, instrument, tailwheel, and commercial tickets, as well as worked one full day a week at a truck driving job to pay for them. I was on full scholarship that paid for university classes, and the part time work was to pay for the flight training. I also used federal student loans to a large extent.

Obviously money was an issue for me since I come from a poor family, but if I had the money I would have also obtained my multengine add on plus all the instructor certificates. I have heard of people doing all that while obtaining a 4 year degree in something else. They are go-getters, but it can be done.

After a while you will hopefully graduate from university and apply to med school. Bear in mind you need high scores to get in, so don't get too caught up in flight training in the meantime. Do it as a hobby. Doctors are important too, and you should make becoming one your prime focus at least until you decide it is not for you any more.

Since you already know that airline careers involve a slow climb to the top, I would make that your fall back option, and be serious about medicine. There are doctors who switched careers to piloting, and are happy and successful in the change, but they already had the money to do it before they switched careers. You will live on peanut wages for a number of years (5+) if you decide to go the airline route. That's why I never did it. The person who said to look into military flight surgeon also had a good idea.

Best of luck.