Regret having a baby right after my son😩

Im 4 months pregnant and have a 1 year old son.. its so hard.. right now im not at my best.. i been throwing up so bad idk why with my son i didnt do that. I have major migraines!’ Im tired all the time ! I cant do this. .. 😪 i dont want this baby😰🙏 mentally and physically i cant .. i was on birth control to when i got pregnant with this baby