Concerned and freaking out!

So I have been seeing a fertility specialist since the beginning of the year. We just found out I’m pregnant a couple weeks ago on our own without treatment. He’s been having me do blood work 2-3 times a week since and other than adjusting my progesterone meds everything has been ok. They had scheduled me for a 5 1/2 week scan later this week but I notified them I would be on vacation starting tonight. They then tell me I need to come in the next day, which was today for the scan because they need to make sure the pregnancy is not in a tube and not to be worried they’re just nervous about me traveling...ok...so I go for the scan, I am exactly 5 weeks today. I’m a nurse and although I am not an on nurse, I can figure some things out. So I see a sac which is confirmed by the tech and she hands us a pic, we go home.....I get a message from the doctor’s office telling me it is very important that I get a follow up scan in 5-7 days. Again I tell them that won’t be possible because we’ll be on a cruise ship tomorrow. They tell me I should stay behind if I can’t do the scan because they don’t want me traveling until a heartbeat is confirmed....I told them I demanded to speak with the doctor himself at this point. Why would you ask someone to cancel a family vacation involving 7 members and lose thousands of dollars if there was no concern?! Why can’t it wait until next Friday when I come back?! They’re telling me there’s no concern but again it’s not like you’re asking me to cancel a date night....there’s a lot on the line for something you’re telling me has no real concern......any advice? Input?