Ugh !!! Stressful !

Well I finally got my POSITIVE !and now I am at 6 weeks my ultra sound is in 2weeks and I have mild cramping when I sit or lay down and in my lower back as well as light pink bleeding that started today. The last week it was been dark brown( old blood ) and now this ? Has anyone else had this before ? Should I be worried? Should I go to the doctors or is it safe to wait till ultrasound in 2 weeks ?

:(

Please let me know so I feel better it’s my first pregnancy 😩!!