Pregnacy and depression

Hannah • Girl 2016 Boy 2021
So I have a very sensitive topic that is hitting real close to home with
Me right now...
Me and my SO who I love oh so very much, just found out we are going to have a baby. We tried for this baby and got pregnant right away. I have always dreamed of being a
Mommy since I was a little girl and my favorite part of life is getting to be an aunt to my amazingly beautiful nieces and nephew who I adore! We were so excited to try and get pregnant and then  right in that two week waiting period before I could test, I had worked myself up so much that it was going to be negative that I was so convinced it just wasn't gonna happen the first try. Surprise I took a digital pregnancy test and I set it in the bathroom and let Chris look at it. He was so excited and paced our house waiting for the results at I sat there emotionless on the couch telling him it's gonna be negative.. To my surprise he brings me the test with tears in his eyes and says its positive and we are gonna have a baby! 
I was in shock that to him, my reaction  was disappointing. But I assured him that it was just shock and we should take several... Yes I said several more tests through the weekend.... After three different brands and 6 tests later all came back positive.. I was happy but scared.
I am just about 5 weeks now and the feeling I am feeling is just so unlike me. I mean I get in pregnant and I already start to feel different and uncomfortable but I feel emotionless and unattached to this baby. This baby I have dreamt of since  I was a little girl! I feel so extremely depressed and anxious and not excited cause at all. And as I sit here and tears well up in my eyes as I am about to be oh so brutally honest... I think, what if it doesn't stick. What if this pregnancy and these awful thoughts and feelings I have, just doesn't stick. 
So many women try and try and try to become pregnant and can't. So many people lose a child and are suffering from that and I know what I'm thinking in my mind is so wrong and I feel so much guilt but I can't help this depression I have developed and the lack of joy I feel during this time. I keep thinking and saying this is a burden. Even though in my heart I know it isn't and it's a blessing from God it's just my mind is not my mind anymore. I don't feel like me. I'm not myself and I am so distraught. Has anyone ever felt this way? Has anyone ever suffered from antepartum depression?