So let's summarize:
You're in a happy relationship with someone who has been with you through a good portion of your education, supporting you and generally -- it seems -- being a good partner.
You were never that popular before, but now that you're a doctor women are finally showing you some interest. Unless something else has changed, it's pretty safe to assume that these women are only really interested in you because you're now a doctor (and a better "catch" financially.) Some of them have even been tasteless enough to hit on you in front of your girlfriend, so... these are not exactly "quality" prospects.
You want to know if you should trash what you have (and make no mistake: if she has any self-respect at all, your girlfriend will forget you exist the instant you dump her for greener pastures now that you're "worth" more) so that you can pursue these women.
So what's going to happen if you do that? You dump your girlfriend, probably breaking her heart and knowing you can never have her back, or get back what you have now.
You start dating around with these women. And although it's clear enough right now, it becomes even clearer that they're less interested in you as a human being than they are in marrying a doctor. Which is always a great reason to start a lasting, healthy relationship with someone, right?
Is that what you want, long term? Because after the third or fourth woman who is quick to whip out the, "I'm dating a doctor!" thing on Facebook, is it really going to seem as awesome and fulfilling? Or would you rather have a partner who whips out the, "I'm dating an awesome man who I love unconditionally"?
And your girlfriend? Is it going to feel great when she moves on, as well? Find someone she can support and value -- regardless of what they do -- who will support and value her in return? Do you look forward to seeing happy Instagram pics of her and her new beau? Her wedding pictures? The life she's building with someone who didn't need someone to date around and have his ego stroked?
Look. If you don't love your girlfriend, or you think you're better than her... let her go. Go do your thing. But she's not a used car. Don't treat her as if you can just park her in the garage and tool around in a hot new convertible until you get tired of it, then go back to the more reliable model. Let her find someone who will actually stick by her, and not be looking for someone to preen their ego.