Mental Health issue

Hey you lovely lot I have a question for you I have severe anxiety and suffered with depression from 14 I'm now 26 the doctor has put it down to a chemical issue as there's no real trigger but I am now pregnant with my fourth baby and have had to stop my medication and because it wasn't planned as such I had to stop them quickly anyways I'm struggling with horrible thoughts and worries that are completely irrational and I was just wondering if anyone else has been in a similar situation that could give me some techniques to help me my partner doesn't understand just tells me to relax and my children are my world but they don't understand when I'm having a 'bad day' and it's breaking my heart I'm ecstatic one minute and in the next I want to get in my car and never come back