I seriously think pregnancy can be addictive, i so know what you mean! After having Grace for months it was like my body was longing to be pregnant again, I loved being pregnant and missed is so much. I have managed to wait until Grace is almost 3, not quite sure how I managed it but after a number of months I just thought I must enjoy my daughter and spend a much quality time with her as I can - that got me through! Once she hit 2 the broody feelin started again!!! I would say don't put yourself under unnecessary financial pressure as it sounds like you will be stuck in your 2 bed flat for a while longer but obviously if it's what you want who am I to tell you otherwise! Lol!!
Wish you all the luck in the world xxx