Down in the dumps?

This post is not meant to be insensitive. I know there are tons of women out there who tried SO long and hard to finally get pregnant with a sticky baby. This is just one mama looking for support from others. 
Our baby was a "surprise" addition. We wanted kids eventually, but we are still pretty young and not quite financially where we wanted to be before conceiving. However, when we got that first positive pregnancy test, my husband came to terms with it pretty quick and is now SO excited to be a dad.
I, however, am struggling extremely hard to find any excitement in this. I find myself angry a lot of the time- at myself, for not preventing the pregnancy, and worse, at this helpless unborn baby for making me feel rundown, sick, and fat all the time. I can't seem to come to terms with how my body is changing and how my entire life is about to change.
I know I'm not fun to be around anymore. I'm trying really hard for my husbands sake to act excited, but it's wearing me out to pretend. Are there any other mamas to be that are feeling this way? I know part of it is definitely related to hormones. If pregnancy depression is a thing, I'm pretty sure I have it. How can I fight it? I want to be as excited and to already love my baby just like everyone else on here but so far I'm feeling depressed and unexcited. We have our gender ultrasound soon and I'm not even happy about it 😢