Hello! It would be great if someone can give me some advice/comments on this!

I just turned 20 and recently went to the gynecologist for the first time after suffering from vaginal itching for a year.
I had no idea what to expect but before I knew it, my legs were on the stirrups and the doctor was trying to insert the speculum inside me. It was so unexpected and so painful; I was freaking out because I never had anything put inside me.
The doctor couldn't get it in because I couldn't relax enough, so she said something about doing an ultrasound through the rectum. After, she said she put a pill inside the vagina before sending me off.

....what exactly happened?! What's the rectal ultrasound for? If she was able to put the pill inside, does that mean she was able to insert the speculum inside later? I have some anal discomfort now following the test too...
She didn't explain the process or purpose of each process, and now I'm kinda scared for my follow-up consultation next month...

Also, is there any way to make my future trips to the gyno less painful/difficult?

Thanks in advance!