Shorter cycles?

My last 6 months of periods have looked like this: Oct- period lasted for 6 days, 21 days then another period. Nov- period lasted for 7 days, 23 days then another period Dec- period lasted for 7 days, 21 days then another period Period lasted 8 days, 21 days then another period Jan - period lasted 7 days, 19 days then another period (just finished 7 days long) Why is my cycle so short? Would I likely be ovulating? Does this affect ttc chances? I’ve only just realised and looked back to see it’s been like this. I have a 2 yr old and still partially breastfeeding if that info is helpful? Any clues?? 😩😩