I have last period 28 December 2014 I have all symptoms nusia,sore breast,food craving,constipation on 18 January 2015 am I pregnant

Did you have sexual intercourse since your last period? If so, then yes you could be pregnant. But there is no way for us to tell whether you are or not. What I can tell you is that the first manifestation of pregnancy is a missed period. So the symptoms you are experiencing are NOT due to pregnancy (doesn't mean you aren't pregnant). You need to wait until at least a week, preferably 2 after your next period is due to start testing.

The only way to determine pregnancy is with a urine test, a blood test, an ultrasound, or giving birth. It cannot be determined online, and it cannot be determined based on symptoms.

If your period is at least a week late and you've had intercourse before this late period, then test using first morning urine. If that test is negative wait for your next period. If you miss it then test again or get a blood test done at the doctors office.