If I had a transvaginal ultrasound and they said I am 7 weeks and 1 day, does that mean that I conceived 7 wk 1 d ago? Or 2 weeks after that?

2 weeks after. The estimated age of the pregnancy that you are given during an ultrasound is an estimate of how long it has been since the first day of your last menstrual period. Ovulation and conception occurs, on average, 2 weeks after that, but varies from one woman to another. Also, the estimate of 7 weeks 1 day they gave you is only accurate to within about 1 week.
5 weeks ago. Conception occurs two weeks after the first day of you last menstrual period presuming a regular cycle and usual facts. So if you are 7 weeks after your LMP you likely conceived about 5 weeks ago. Take Folic Acid 1-5 mg daily and good luck!