menstrual cycle question .. getting shorter then stopping?

im a little confused right now .

my periods have Always be regular .( they have had their slight changes as ive got older , but nothing major)

i had my son almost 17 months ago ,

my period returned 10 months ago ( after breastfeeding was cut down )

they were back like clockwork for 6 months , then on the 7th month the cycle was down to 26 days ( normally 30 days ) on the 8th month the cycle was down to 24days . 9th month it was down to 20 days and then this month it is yet to be seen. and we are on about day 34 of a cycle .

i have taken 2 pregnancy test . both negative .

even tho im getting pregnancy symptoms

but now im starting to think that maybe i just skipped a period this month.

which i have never done before.

Does any one know why your menstrual cycle would get shorter and maybe stop ?

or is it possible that i am pregnant and its to early to detect it ?

i understand ur not doctors , im looking for personal ( or friend of a friend lol ) experiences

i will be booking a doctor appointment next week if i still havent got my period .