Atika I think the nurse is right that until 6 weeks you wouldn't see anything on the scan anyway. However she is wrong about the pregnancy test - you will still show a positive pregnancy test for a while even if it is a miscarriage as the levels get pretty high in the week or 2 since test day, and it takes a while for them to come down to below pregnancy test level. So a simple urine test will not tell you much.
I would push for HCG blood tests, you need two tests a day or two apart, as that will show if the numbers are still increasing, or are going down, that should definitively tell you if you are miscarrying. Are you NHS patient? You might be able to get the blood test done privately if they outright refuse, at our clinic it is £50 for a HCG test, not sure if that is an option for you.
I would say though, it sounds like quite a short bleed to be a miscarriage even that early, especially if you are still on progesterone? I miscarried at 5 weeks to the day last August and even once I came off progesterone the red clotty bleeding went on for a full week and then I had a week of brown stuff. I had to have blood tests to confirm, the urine tests were still positive for a while after.
I really hope it's not the end for you. If you google you find lots of stories about women who had awful bleeding throughout pregnancy even early on. My SIL is one of them, I can't remember how many times my brother drove her to the early pregnancy unit over her pregnancy and my niece is a gorgeous little 18mo now. So it is possible things are still OK. I hope you find out sooner rather than later, I don't think your clinic is being very helpful :-(
I had a scare on sunday night, woken up by DD at 2:30 am I went for a wee before going in to her room and was bleeding, bright red. Obviously didn't get any sleep afterwards and then spent the day feeling really sick - DH had to take the day off - thought it was morning sickness but think it may have actually been a stomach bug as today I feel still queasy but nowhere near as bad. But fortunately the bleeding stopped almost immediately and hasn't recurred so fingers crossed it is all OK.
Lily hope you get good news about fertilisation!