Debt collectors

So I had a letter through the post from the courts saying I owe money and I need to pay it, I had to fill out a form to say how much I make a month. I sent it off. I didn't hear anything back, and now I have a letter to say because I haven't been in contact and haven't made payment they're sending bailiffs to my door in 7 days. I'm freaking out. I'm 4 months pregnant and have a 7 months old baby. I'm stressing. I don't work and have no income. We live on my husband's wage which isn't great. Has anyone got any advise please