Postnatal depression - is it? If it is, then what?

[twolittleboysonetiredmum]

I'm hoping this is the best section for this post.
I had dc3 9 weeks ago and am unsure whether how I'm feeling is age/exhaustion related or something more.
I've become increasingly obsessed with my own and everyone else's mortality and feeling quite nihilistic. I don't feel life is pointless as such - in a suicidal way - but do wonder at how pointless it all is as we're all going to die. I've become very anxious about dying but it's not stopping me doing everyday things. I've just turned 35 and wonder if the ageing thing is part of it?
I'm also being very self critical this time round. I feel awful I'm still so overweight/not exercising/not cleaning etc and am exhausted from trying to be supermum. I'm worried about letting my other two very young dc down - 2 and 3. My dc3 sleeps like a dream but I am still finding it challenging which seems ridiculous.
Basically - should I see a GP? Is this my personality now or am i depressed? If I am, what would they do anyway?

I'm Also very weepy but I guess that could be hormones/tiredness eugh

If I were you I'd go and see your GP. If it is pnd it would be a good thing to start getting help now rather than wait. obsession with death was one of my symptoms.

Thanks for the replies. I have a supportive husband but he's bogged down in it all and I wouldn't feel comfortable dumping on him emotionally really. We have lots of family but no support from them sadly.
What would the GP actually do if I have got it? I'm a bit worried about either a) crying there or b) there not really being a problem and it's just standard mid life crisis/postnatal exhaustion crap. Eugh.