I had depression during my first pregnancy, and wished I had insisted to the doctor that I know myself, and I was feeling more than just the hormonal changes. There are safe meds out there, and great counsellors who specialize in pre & post partum depression, and it's best for you and the health of your growing baby if you can get help.
Depression can be debilitating, and it's not your fault.
Once your little one arrives - everything is going to change (in a good way!), but your hormones get really wacky and your body goes through a real downer stage - and if you don't have a handle on the pregnancy depression, the post partum can be brutal, and makes it very difficult to enjoy your new little bundles' first few weeks/months of life.
I'm saying this from my own experience, and it might not be exactly how you are feeling, or what you will experience - so take this advice with a grain of salt and use your best judgement. Do not feel bad getting support from friends/family/doctors/medication. Do whatever you need to, to make sure you and your little one are happy and healthy.
I hope you feel better soon - and feel free to message me. I've been through depression during and after pregnancy, and will help/listen/support in any way I can, if you want.