Starting Cerelle (mini pill) - what counts as day 1 of period?

[Jen321]

I've just started taking Cerelle, it's the first time I've taken any contraceptive pill. The leaflet says it works straight away if I take it on day 1 of my period but that I need to use extra protection for 7 days if I take it on day 2-5. I noticed around midnight last night that my period had started (it probably started 2-3 hours before that). I didn't take th first pill until 10am this morning - does that count as day 1 (as within first 24 hours) or day 2 as it was the next day?

Thanks in advance for any advice!