No heartbeat 6w3d - too early?

Hi ladies, I'm not sure if this is the right thread, but I was hoping I could get some advice. My last period was on the 5th of Feb, so when I had my very first ultrasound on Monday 03/04 I was expecting to be around 7 or 8 weeks pregnant, however the sonographer said it was only 4-5 weeks based on the size of the yolk sac. At that stage he could see no embryo, so he said to come back in 2-3 weeks for a repeat scan.

Yesterday, which was 2 and a half weeks after the first scan, I went back. We could see the embryo, and when he measured it from the bum to its head, the system said I was 6w3d along, however the sonographer couldn't detect any heartbeat (he tried for a few minutes). He implied that it's all over and the GP would be in touch to discuss the next steps. He didn't say if there was something else indicating a miscarriage, just no heartbeat.

I also must mention that I've had a little bit of brown discharge over the past few days, no cramps.

My question is, if at the first scan he said I was 4-5 weeks along and two and a half weeks later the embryo was exactly 2 and a half weeks older (6w3d), should I try and get a second opinion as sometimes 6w3d is a little bit too early to detect a heartbeat (my bladder also wasn't that full which apparently makes detecting the heartbeat harder)? I don't want to get my hopes up, but at the same time I thought he was rude for not suggesting I come back for a repeat scan. Do you think I should ask for another ultrasound referral to get a second opinion in a few days' time? Thank you so much xx