Should I test? Advice?

I took a couple of tests and got faint positives. So, I went and got blood work done. When they called with the results, she said it was positive and that it was a 79 (my hormone level). She said I was 3-4 weeks pregnant (doc appt was on the 20th of July). My question is should I test and see if I get darker lines then from the first ones. I was also wanting to know. Is 79 bad? She said to come in a week from the 20th and get another blood test done, so they can know when to do an ultrasound. I've been so nervous ever since that call. 😢