missed periods

I am 25 years old and have a 2 two year old son. i am desperately wanting  another baby now and we are not taking precautions too. my expected periods date for this month was 9th Oct but i have'nt received my periods yet by 27th october. I got my pregnancy test after 9days of my expected date but it turned out negative. but the problem is when i was expecting my first son three of the tests taken around nine to ten days of my expected date came out negative too, though i was expecting. Now i just want to ask you since it had been around 20 days up is there a chance of still getting pregnant, though my periods date keep on fluctuating up for around 3-4 days. like in august it was 2nd but in sep it was 9th and for oct i am still waiting. And plus i want to know what should i do to get my periods on time so i can increase the chances for getting pregnant soon.

[H1228]

I would see a doctor so you can plan out when you're ovulating and make sure you aren't pregnant right now.