you can wait to see if your period comes, and then test[in the morning], if you get a positive you can go to the doctors right away or the next day for a blood and urine test to be done to make sure you are 100% pregnant.
Some women experience morning sickness, and some dont, some have sickness all the way through their pregnancy too.
You could just be stressed and that is giving you cramps and nausea.
I waited a few weeks before i told my family, my mom didnt say much she was upset though i knew that much, my step mom and dad had a more serious talk with me than my mother did, but i thought it was better to tell them sooner than me waddling in and breaking the silence. I knew they werent going to be thrilled, but they had every right to know about me being pregnant at 18 [19weeks&4days today!] At first, they probably arent going to be happy about it, and really disappointed, but the sooner you tell them the sooner they can adjust to the situation and will come around.
if your school knows, they will right away call your parents and tell them.
So its better you tell them than someone from school telling them instead.
The earliest you can test is 4 days before your period as well.
good luck!