With 10 positive tests, there is
no doubt. The only time
pregnancy symptoms (or lack thereof) can possibly be cause for concern is when they all of a sudden just stop. Literally there one minute, gone the next. Even then, there is often nothing to worry about.
Don't get an ultrasound too early. Prior to 6 weeks or so, they aren't going to be able to see much, and that can cause more worry then anything else. You can ask your Dr. for 2 blood tests.