How do you balance the happy and the fear?

Karen

This morning for the first time in my life I got a BFP. It was faint, but clearly there. It has taken 3 rounds of

<a href="https://glowing.com/glow-fertility-program">IVF</a>

and multiple transfers..... but holy craps there were 2 lines this morning. My beta is tomorrow, so the faint line is easily understood. I am 41, the embryo(s) were not tested. I am pretty sure that means I have about a 60% chance of miscarriage. I am excited and terrified at the same time. How do you balance this ?