Anxiety...

I have my anatomy scan on monday i will be 21 weeks +3 days and idk whats wrong with me but i just keep thinking about the worst! I found out what i was having at 16 weeks +5 days at a private 3d ultrasound place and she said baby girl was doing fantastic! But it was just a scan to determine gender.. and since its been so long my mind is racing! Anyone else feel like this or am i just crazy!?