Unknown Caller harassment

I’ve been getting 20-30+ phone calls a day, everyday, for the past week. All by either “Unknown Caller” or “No Caller ID”. These calls are happening 24/7. I can’t even leave the sound on my phone anymore. Usually it’ll call and hang up on the first ring. Sometimes it goes to my voicemail though and I hear deep breathing. One time I heard someone laughing. I don’t know anyone who would do this to me. It just happened out of the blue. Does anyone know how I can stop this from happening? I don’t want to change my number because it’s such a hassle calling professionals (doctors, school, bills, etc.) who need my phone number. It’s really really freaking me out though and I don’t know what to do.

Update: It just happened when I posted this. I picked up and there was clearly someone on the other end but they didn’t say anything. I’m so freaked out right now.