Hi - so sorry that you've had to go through this, and you really should have been referred for tests after 3 miscarriages - but these things sometimes happen.
I am currently 6 weeks pregnant after suffering 4 mc's.
My background is 1 mc, then DD born five years ago, 2 more mc's at around 9 weeks, then another at 5 weeks.
I had all the usual tests done on the NHS after my 2nd mc, and they all came back clear - I was basically told that I was just unlucky. After my 4th mc, I thought "Bollocks" to being unlucky - something was not right, and I would never get a baby unless I did some furthe research.
I found out about NK cells, and have been seeing Dr.Shehata at the miscarriage clinic in London. He did blood tests and I have very high NK cells - basically, my body attacks my pgs as it would any other invading foreign body or germ. You can have had children, and this can still happen.
I am now on steroids daily, aswell as aspirin and progesterone. I have also had an intralipid infusion and will need another one in 2 weeks time.
Obviously, I am still not beyond the magic 3 months yet, and don't know if this treatment will work or not - I just think it's the best and only chance that I have got. We have had to go private for this, and we expect to spend around £2000, if we get that far.
Go for the tests with the NHS - you may have something going on with your blood, and it could be easily sorted. If these come back clear, you may want to consider the NK cells route.
I hope you get some answers, as that's the worst thing about recurrent mc - the medical profession can be a bit baffled by it, but there is hope with the right treatment and diagnosis.
Take care x