Pregnancy blues

So I went to a baby shower today for a friend and had a really hard time seeing her pregnant and seeing people with their babies. About two weeks ago, I took some pregnancy tests after being extremely nauseous and they all came back positive. I was so excited! Then, a few days later, I started my period and was devastated. I thought I would be fine today but was so upset that I had to sit there with a stone look on my face to keep from crying. I'm sooo happy that my friend will be welcoming a baby! I'm just so sad right now that I'm not pregnant like I thought I was. It's difficult to explain. I wish I didn't feel like this. I'm so ready to be a mother and things are just not working out the way we thought they would. I feel very selfish for how I felt and acted today. I was so in my head that I couldn't snap out of it. I'm asking for prayers that God will remind me that He has perfect timing and that everything will work out according to His plan. Also, does anyone have any ideas on how to work through this? Thank you!