suicidal thoughts in pregnancy

Please do not judge... I really wish I didn't feel this way.. and trust me if I could change it I would...
After the excitement of finding out that I'm pregnant; I've found myself extremely depressed and holding onto the past. I feel so stuck now that I have a baby on the way and I'm missing somebody tremendously 😔😔 
I've been having overwhelming thoughts of ending everything since I can't change what is.. 
It's breaking my heart feeling like this after wanting to have a baby for sooo long now.. why do I feel like this 😭