pregnacy and depression

I'm new in this forum. I'm not an English native speaker, but I think that I wouldn't find something similar in my language, so I hope you can live with that and accept me here. I looked for this group because I need to talk to someone. I've been suffering from depression or better different depressions for 15 years. I had phases when I was better, phases when I took medication, phases when I did not have to...I've been doing psychoterapy too. Somehow things have been under control for a while, with ups and downs but at least without any suicidal thoughts. I found a very nice man who loved me and we have been married for 7 years, we got a baby 2,5 years ago and we have everything in a way, and just this depression is haunting my life. Not always, but often. 6 motnhs after I gave birth I was pretty down and even if I loved and I love my small boy above all things on earth, I was close to a sort of mum's burn out and I had to take medication again. This was also the moment I started working again and in a not very nice job, so I guess the hormonal changes, tiereness after birth and sleep deprivation contributed to that. Anyway, I started taking Celexa, but I stopped recently because we want to get a second child and I can't take the risk of getting pregnant while taking anti-depressive medication. My seratonin level is very low (my last blood test showed me a result of 11 when the normal level should be at least 60) , so I'm not really doing well and I had already a few bad arguments with my husband because I always feel tiered and without energy and he claims I'm negative and always want to see the dark side of life...so basically, without anti-depressives is not being easy and I wonder what to do. I want to get a second child but I also want to have an healthy pregnancy (this means without medication) but I wonder if I'm not going to have a marriage crisis instead. I'm also not happy with my job at all and when I feel depressed and jsut want to quit it, but I don't think this would be a good idea.... I don't really feel sad, but tiered and frustrated with the whole situation so I wonder if someone here has gone thorugh some similar situation or can somehow help me to cope with all this better