Birth control pill, regulation after the pill.

I got off birth control in April. About 19 days after I got off the pill I ovulated. Since then I have been tracking, the two following months I ovulated on CD 18, last month, CD 16 and this month I am on CD 11 and am starting to have signs/symptoms that I will ovulate in the next 3-5 days. Did this happen with your ovulation as well? When I ovulated on CD 18 I thought “oh well this must be my normal” and then as it shortens I’m wondering if this is normal.