So big for 4 weeks?!

Priscilla • Mummy to 2 beautiful boys, ttc our 3rd this year but had 4 miscarriages, finally got another BPF in November and we are due our baby mid 2015 :)

with my son the top photo is the ultrasound at exactly 4 weeks, the bottom one is the ultrasound at exactly 4 weeks with the baby im now carrying (5 1/2 weeks)

Show me your ultrasounds at 4 weeks? Do you think it looks big and do you think its twins?