Possible twins?

Okay this might seem like a silly question lol but I need to ask. Back in January I had my first dose of letrozole. My doctor said it might stay in my system for a while and I had to keep getting blood test done every month.

Is there a chance I still might have conceived twins? Also twins run in my family on my mother’s side.

Conceived somewhere between end of April and May 3rd. 7wks & 2days today