Cyc 25dys, began 10/4. sex10/9. planb 10/11.(also took planb8/4).this month no period! 4 neg prg test this month. feeling nauseous in mornings and night, dry mouth/ thirst. had lower ab pain 1-2days when lay down. what's causing nausea, and no period?

Pregnancy is very less likely with the clinical scenario you described. An acute illness may delay the menstrual cycle not mentioning plan B may delay period sometimes. You should see your primary doctor for the current symptoms which may not have anything to do with pregnancy.

Many reasons for no cycle, the addition of the morning after pill can cause this, also regular birth control pills as well. Exam and discussion with your doctor may be needed, to achieve best care plan, and help your concerns to alleviated.