Don't worry - you are 8 weeks pregnant and with all the hormones I am sure we are verging on depressed during this first trimester.
I'm now 12 weeks with DC2 - and oh boy how desperate I was for another baby, how gutted when it didn't happen first cycle
and how thrilled when it happened 2nd cycle.
But from about 5 weeks in I have just felt ill, very sick and tired. Am dreading the rest of pregnancy and then how on earth I will cope with newborn and 2.5 year old.
BUT. I was exactly the same last time round and I am sure I get depressed in the first trimester, along with just being very ill (signed off work both times for a few weeks).
Once I get to about 15 weeks, something happens, the mood lightens, the hormones settle, you stop feeling ill, you've seen your baby on the scan wriggling around and waving his hands, you feel the baby kicking etc. And it becomes joyous (if uncomfy towards the end!)
And once you have the baby, yes, life changes dramatically, but in my experience it is the opposite of the first trimester - there are all these feelgood hormones (from breastfeeding?) and adrenaline flowing round. And you are so thrilled to have done labour and birth and to have your own body back after 9 long months. Although the newborn period is tiring, I was on a kind of high for much of it.
I really do think in another couple of months you will be feeling much better, physically and mentally. For some of us, the first trimester is just a grim three months to be got through as best as we can. I was uncomfortable in the last trimester, awful heartburn, difficulty sleeping, but my mood was nowhere near as depressed as it was at your stage.
Baby steps - not too long now before your 12 week scans. That does change things - seeing baby on the screen, you start bonding with him/her, at the same time your hormones are starting to settle.
It will get better promise! The first weeks drag horrendously, once you have had the 12 week scan, time speeds up, it really does.