First ultrasound, bittersweet moment

Went in for our first ultrasound today! Saw our little baby and baby looks good and has a heart beat of 155. I am measuring 8w 1 day but we are keeping my due date of August 15th as it was only off by 4 days. So I am 8 w 5 days today! Bittersweet moment was there was another sac with a fetal pole but no heart beat 😞. Doctor said that this is a case of vanishing twin syndrome and my body will just absorb the empty sac and won't cause any complications or problems for our healthy baby. It's going to take a few days for this all the sink in but I am happy we have a healthy baby growing everyday.