I'd love it if my womb lining was 5.5 mm!
Mine was 10 mm on last measurement shortly after my bleed and I reported to doc (I said this on another thread) and asked for norethisterone to thin it by sending a message to the practice phramacy. They prescribed this without even asking to see me nor suggesting I was scanned to check it had thinned! I feel most ignored!
I really dont know why they have fast tracked you if you;ve only been taking it since November as Taz says - this is quite normal, to bleed - though if these bleeds persisted then it would be good to have a scan.
Some women never settle on conti HRT and swap to sequi HRT for this reason, even when post-meno.
Really try not to worry!!! Hopefully all will be well - and do let us know

Hurdity x