Random light period - safe to TTC?

[Zabadee]

Just finished a random light period (3 days instead of 5). No other issues with cycle. This happened to me once before and I then went on to conceive that cycle and miscarried at 10 weeks. I'm keen to avoid that again.

My thoughts are that it could be...
A) for some reason I had a thinner lining last cycle and therefore there's less blood to come out. A new lining will soon build up so assuming this cycle is normal (obviously I can't know this) then the lighter period is related to last cycle and won't affect the new cycle.
B) the period I've just had was lighter because not all the blood has come out. I have two 5cm fibroids so wondered if some blood is getting stuck behind them. If so, does leftover blood from the previous cycle make miscarriage more likely?

Any ideas?

Are you sure you’re not pregnant?

Pretty sure yep. Did a 10miu sensitivity test at 13dpo and BFN. Pretty conclusive. And period arrived on the exact day it does every month, with perfectly normal cramps etc.
This did happen once before too, so I have form! 🤣

Also I do BBT and my temps have fallen to follicular phase level as expected. So definitely not pregnant.

Just hopefully bumping 🤞