Period trouble

Pip • Pregnant with a little boy • c-section is booked for 4th July 2016 at 8am ✨
I came on my period on the 4th this month, I came off on the 9th. Then all of a sudden yesterday I had all period symptoms, then started a really heavy period like I do when I start each month. Why did I stop and then start again? Messes up my ovulation days etc now 😪