Ttc long term coming on my period early

[louiser91]

Hi
I was wondering if anyone could help me ?
I'm 2+ years ttc I'm on my 5th round of clomid.
My periods have always been 28-30 around 6days long, however my last 2 periods have been different?!? Last month I had a light brown discharge for 4 days (sorry tmi) and then I bled for 8days. And this period I have come on on day 21 which has never happened to me before ?
Is this normal ? I have no idea like I say it has never happened

Thanks !