It's your call thou if u want to get blood on Monday just to ease your mind or wait till Wednesday. Wednesday probably can give you a definite answer thou I think.
How many day post transfer are you now and is it a day 5 or day 3 embryo?
I know stressing not going to help but that's ivf journey always waiting and stressing bout every little things happening to your body. All I can say is hang in there and it will work itself out ☺