feeling really low

This is my first pregnancy, and I’m 5 1/2 weeks along & I’m feeling excited about being pregnant, and becoming a mom, BUT I’m incredibly sad as of late.. I know hormones are changing and my emotions will be here and there, but will the overwhelming sadness feeling stop at some point? I sort of feel like a storm cloud is just following me around. My husband is very supportive of me, but I can’t even explain why I’m so sad, let alone have him understand where I am. Has anyone else been through this? Tell me it goes away..