How many calories should I be eating?!?

Melissa • My husband and I were blessed on November 19 2015 with our son Nolan! Currently pregnant with baby #2 👨‍👩‍👧‍👦
Hey ladies! So I started out my pregnancy at 260lbs and I'm almost 18weeks now and I'm down to 235, dr said its fine even good that 
Loosing some weight as long baby is growing which he/she is. I've been trying to find some sort of calculator to help me determine how many calories I should be eating a day but can't seem to find one does any know of any?? Thank you :))