Vaginal ultrasound

I have a vaginal ultrasound coming up on the 24th. Going off my last period I should be 7 weeks and 1 day then, making my due date March 11, 2018. I believe I got pregnant a couple weeks after my last period so I’m just curious if there is a possibility of not seeing anything in a vaginal ultrasound like in a regular one? They are giving me one so early because i lost my 1st daughter at 20 weeks last year so they are keeping a closer eye on me this time. I don’t want to freak out if they say they don’t see anything if it’s too early to see anything. Or is that bad if they don’t see anything since it’s a vaginal one? I hope this makes since lol thanks for your help!