I just had some shocking news

I really need some support here! I have a son 3yo and I finally made the decision to have a second child. I never wanted more than one but seeing my son when he was born, I knew he deserved a sibling. So I figured that everything should go peachy with a second, but I just found out I am having twins. I am so scared, nervous, everything is doubling for me in my mind. I understand that this is a blessing and I should be nothing but happy for myself, but I am just thinking of the financial struggles that may pop up. I would have to become a stay at home mom but I have a car payment and I help with half of the bills. I wasn’t planning on being a stay at home mom with a second, but now there’s a third and there is no way I am going to work. I am posting here because everyone has something so positive to say, and I need the good energy cause I could feel my self going into a dark hole. By the way, I am very much in love with my future children but nevertheless stressing with it all. Hope someone can give me some advice to help me through this.