yolk sac disappeared ?

i had my first ultrasound (bottom pic) on tuesday, i was measuring 5 weeks 6 days. everything looked perfect and we saw the yolk sac very clearly but no fetal pole. last night i had a small clot looking thing when i peed and then bleeding. i’ll post pics below. i came in today for another ultrasound to see what’s going on(top pic), we saw the start of a fetal pole and even saw some flickering which he said could be start of the heartbeat. only thing is now we were unable to see the yolk sac. has anybody else had something similar happen and still been okay ? he’s not too worried because my pregnancy did grow and i am now measuring 6 weeks 3 days. i’m just finding it really hard not to worry and stress. pics below.

ultrasounds

bleeding and clot

the bleeding did get a little heavier than this and also was a little brown