Ectopic in June 2018 and still have mass in tube

I had an ectopic pregnancy at the end of June 2018 and was treated with 2 doses of methotrexate. I was about 7.5 weeks along and over 3000 beta hcg. My levels went down to 0 after a few weeks but during my ultrasound at the beginning of August, it showed that I still had a mass in my tube. I had my 6 month ultrasound checkup on December 10th and my family doctor told me that nothing's changed and I've still got a mass in my tube.

I'm so upset and disappointed. My doctor said to wait another 6 months for another ultrasound, but I'm fearful things won't change again and I'll just be wasting time.

Has anyone else gone through something similar? If so, what came from it? I have an appointment with my ob on Wednesday but she's pretty new and told me everything would be fine within 6 months. When I asked her what would happen if the mass wasn't gone after 6 months, she didn't seem too confident and said it would be (I know, I'm trying to get a new ob but I live in a small town and it can take many months).

Feeling defeated. :(