Has anyone had a transvaginal ultrasound with hcg only at 500 and did they see anything?

They didn't see anything on mine but found a ruptured cyst so I had surgery to take care of that. During the surgery they couldn't find the pregnancy either and my tubes looked fine so they left them alone but gave me methotrexate shots since they said there was no viable pregnancy in my uterus. 3 days after getting the shots, my hcg rose up to over 1500. Now a few days later my hcg has just barely gone down to about 1450. After seeing my hcg rise so much those first few days after the surgery & shots, I'm kind of panicking that maybe they were wrong. Is it possible that they only didn't see a viable pregnancy because it was too early with hcg at 500? Or would that have seen something already?

Either way I think its done for sure now that the levels started to dip and I'm just waiting to see if they think I need more shots since it only went down slightly.