Congrats on your pregnancy. The symptoms you are experiencing are very similar to mine too. When I was about 5 weeks pregnant, I could only sleep for 4-5 hours with frequent wakings. Then of course, the frequent urge to wee came. My bbs were sore since week 5.

As for your U/S, it's normal for your OB to order one at week 19 instead of week 12 since there's really no need to get one this early unless you have some complications. At week 19, the Ob prefers to do an ultrasound to make sure that the gestational age is appropriate as your estimate date of delivery is depended on guessing the date of your last menstrual period. So, with the ultrasound at week 19, it will definitely give an accurate idea of your actual gestation week when they compare the size of your bub. Also, at week 19, you are more likely to be able to tell your bub's sex whereas at week 12, it's hard depending on the baby's position.

Wish you all the best in your pregnancy!