Cant think clear

So 1st of all we wasnt ttc but we wasnt preventing it to an extent.. which was silly looking back as i wouldnt be in this position. I found out a week or so ago im pregnant i had a feeling so tested early and i wasnt unhappy when i saw the bfp just a little scared. My husband wasnt unhappy at the time either.. but when the news sank in an real life sank in the worry set in for us both. We have 3 children the youngest being 18 months. I have mental health problems and i seriously doubt i could cope with a new baby. Another factor is we are not in the best position financially for another baby..(i knew this before i fell pregnant and why im feeling even more stupid) we arnt struggling atm financially but another person to provide an take carw of will really put on the strain. Every logic option says terminate but every single fibre of me says there is no way i will terminate. With that said i have an appointment booked at the end of the month but i dont know if i will go through with it or not. I feel terrible for letting this happen and being so blase an the whole not using contraception. Im not a stupid person i knew this wouldnt be the best for our family at the minute but i still let it happen? I knew all the reasons it would be a terrible situation but i still let it happen. My mind at the min is i dont think i can go through with this termination but i feel maybe my fears will force me to go. I dont know what im wanting from this post maybe someone to tell me i can do it or someone to say sometimes we just cant do it. Sorry if this doesnt even male sense im so confused and distraught.