Timing..

I miscarried in early Feb. - we had sex on March 3 (only time since the miscarriage) and took two positive tests on the 21st. The next day I had bloodwork done as well as two days after that - increasing how it should. I didn't have a period since the miscarriage - so I have no clue how to time it and figure out how far along I am. Go in for an ultrasound next Thursday. Will they be able to see anything?