Help I'm super nervous!

Arlah • 24, first baby! ? MTB
I'm 7 1/2 weeks pregnant and I'm cramping and having like a brownish discharge! I'm freaking out! Want to go to the ER but I have an appointment tomorrow with my prenatal doctor! I had a sonogram on the 25th and they said everything was perfect! This is my first pregnancy and I'm totally lost!