I'm sorry that I have to say this. I may be blunt but it is not through lack of understanding. You are as much a valuable person as the child you will (I hope) bring into this world.
may be forgivable as a mistake to be corrected. Two never is.
You should have taken more care or, if you weren't capable of doing that yourself, you should have made sure that you weren't ever able to produce unwanted children ever again.
You either pay for your mistakes and live with it or you make sure that BOTH kids have a good life. You either have to make sure that they are adopted by people who WANT kids or you have to turn your whole life around. Which is it to be?