Delayed periods, tubes tied - Online Doctor Chats

Doctor :   Hi
User :   Had my tubes tied 3 years ago. I've always had a regular period. The only time I
missed my period was when I was pregnant with my 2 children. Usually 2-3 days
before I'm suppose to get my period, I feel icky, start to get bloated,a little
crampy, all around I feel like my period's coming. Well this happened on Sunday
so I was expecting my period on Tuesday, which is usually the day that I get it
on but sometimes on Monday. Well today is Saturday and still nothing. I have had
the icky feeling all week and I only feel like this the 2-3 days before my
period. That's how I always know it's coming. So all we I've I'm going to get my
period any second and still nothing. This morning I woke up and got a sharp pain
in my left lower abdomen & last about 2 minutes then slowly fated. Also I feel a
little nauseated and just all around icky today, but still almost feel like my
period's coming. Do you know what could be going on? Should I be concerned at
all because I'm really stressing out? PLEASE HELP!!!
Doctor :  
How can i help you?
Doctor :  
let me read
Doctor :   you have the premenstural symptoms
Doctor :  
and your periods are late
Doctor :  
may i know your age?
User :   25 yrs. old and my period's never late
Doctor :   delay in periods can happen some times
Doctor :   if the next cycle also is not regular than you can consult doctor
User :   evn from day1 since I've had my period I've never been late.
Doctor :   ok