Felt beyond uncomfortable at my last doctors appointment

Victoria
A few weeks ago I got my bfp, one of the happiest moments in my life... The next day I went for my conformation appointment I was so excited! When the doctor's nurse called me back she goes ... "So you're pregnant" I said "yes!" followed by a huge smile.. Then the unexpected, she throws this at me ( this was in no joking manner)" So did you do this on purpose or what?" I giggled a little to keep my composure and politely went on to explain to her how happy I was, when the prescreen was over she say this as she walked out " well, congratulations I guess, you can take that how you want to" ... I don't know if she thinks that I'm too young (I'm 21 but am often mistaken for 16) or what but either way, that was super unprofessional!! My next appointment is May 15, I'm nervous that she'll treat me the same way.. Or even worse.. Advice?