Freaking out

All day yesterday my lower back was hurting and it felt like my period was coming, I woke up this morning feeling the same way and when i went to the bathroom there was some discoloration on the toilet paper. I am 7 weeks tomorrow . I don't want to lose this baby. I don't know what to do I might go to the hospital. I'm suppose to have my first ultrasound on Monday. What should I do? Does it sound like a miscarriage?