Maybe you are right jetjets and alternative means of treating PND will be useful for you.
However, if you're having anxious projecting thoughts about your ds's future, and thinking of suicide...you could consider a short course of ADs as a sort of boost to get you doing all the things like exercise and healthy eating you want to do.
In my case depression goes hand in hand with low self esteem and I can't motivate myself to help myself cos I'm not worth it. On ADs the accusatory voices in your head get muffled a bit and it gives you some space to indulge yourself. I wouldn't say they provide a false self; to some extent you might see them as restoring some of your 'real' non-depressed self to you, the parts that worked before the depression set in. (They don't work wholesale anyway- mine never did- still got fed up while on them, just it wasn't as severe).
I sympathise with you though cos I am 8 months pg, quite severely depressed atm and under pressure from midwives et al to start taking the pills again but don't want to pass on drugs through the placenta and breastfeeding to my baby. However I know that my dreadful moods are affecting both him, in the womb, and his poor elder brother (who I have just screeched at this evening because he wouldn't wash his face - they certainly do get more awkward the older they get- but they are lovely too, I only wish I was more able to appreciate him atm). I can't decide what to do either, and wish it was easier.