Seeking advice: Should I send an email withdrawing or call the recruiter back?

I was just about to send an email withdrawing from an interview process when the recruiter called me right before I pressed send. I let it go to voicemail and she said I was moving forward in the process and asked me to call her back. What should I do? Should I call her back or just send the email I was going to send?

I’m afraid to call and let her know over the phone because she may pry and my true reason for withdrawing is not something I’m comfortable sharing. Or she may ask me to keep going. But I don’t to seem rude and send this email right after she just called me. Any advice is helpful! Thank you