So stressed!!!

I'm 19 weeks pregnant with my first baby and me and my boyfriend are trying to move house. It's not going too well as our chain is not complete and we can't look for somewhere to move to until it is. We want to move before the baby arrives as we need my wages to get a mortgage. We could stay where we are but it's not very big and has no central heating which is an issue. All this is stressing us both out so much... And it's made worse (unintentionally) by my boyfriends anxiety over it all. He is worried about everything and although his worry is understandable it is really stressing me out! He is picking faults in our current flat constantly and saying we need to sort this and that... I have tried explaining to him that the more he says these things the more worried I am and I need him to tell me it will be okay if we have to stay here, but he doesn't get it. I'm not mad with him, I understand his worry and anxiety, but how do I block his negativity so it doesn't affect me and the baby?!?! I want to be excited about our new arrival!! It's so stressful. Any advice is welcome ladies xx