Freaking out over upcoming Breast Biopsy

Hi everyone! I'm 41 and just had my first mammogram a couple weeks ago. I got a call back which didn't really surprise me since it was my first one and I have dense tissue. I went and had more imaging and then right after an ultrasound this morning. There's definitely something there, so now I need a biopsy which I'm waiting to schedule. I'm trying to tell myself that it's nothing, but of course my brain naturally wants to go to all the worst places. The place is on my left side kind of near my armpit. I can't feel a lump and my doctor didn't feel one in my physical exam which was the same day as the mammogram. They told me it wasn't a cyst. I have a 3 year and a 5 year old and my biggest fear is not seeing them grow up.

I guess I'm just looking for some reassurance. I know this is common, but I have no idea how I'm going to get through scheduling the appointment, waiting for the appointment, and then waiting for the results. I just keep thinking I have cancer, I have cancer. Any kind words are appreciated.