Pregnancy and medication

Hi all I'm 18weeks + 5 days and I have bipolar. I am on 50mg of quetiapine once a day. I was on 100mg before but managed to reduce the amount by half. I did go down to 25mg but my anxiety was so high they put me back up as they had to weigh pros and cons. I am scared to come of it completely but I want to as I don't want the baby to be addicted. Has anyone else got experience of coming of anti depressants and how you coped?