Do I need to talk to a therapist or something?

I just had my baby in January but ever since then I don’t feel normal. I flip out on my child’s father but everything crazy I send to him I instantly forget about it then I’m calm after..?

It’s not just with him tho I find myself forgetting everything & not feeling nun one min then the next min I’m flipping out again.

Also my grandma died 3 days after I had my baby & my mind has been blank ever since.... it actually scares me because I really dk what’s wrong with me. Idk how to explain it I just .. dk..

I’m only 18 btw.