How to avoid postpartum depression

Ive prayed for this baby for years now. I'm only a few weeks along but the hormones have made me soooo moody that I'm not as excited as I was when I first got my BFP. It's heartbreaking to think about because this is all I ever wanted, and now I seem so ungrateful! How do I avoid PPD because I want to see my baby more than anything and I don't want stupid hormones getting in the way of me bonding with her/him!