36 weeks and tired!!

Hey ladies, I'm after som advice or reassurance. I've always been a bit lazy when it comes to cleaning even before pregnancy .. I just can't find the motivation and when I do it's normally only limited to cleaning one room. I've gotten better since being pregnant and I will tidy, put things away wipe down the benches everyday, make sure dishes are done everyday etc etc. now that I'm on mat leave and only have 4 weeks left im CONSTANTLY tired and battling severe scatia.. My other half understands my pain and fatigue but also gets really annoyed when I don't clean or do a regular load of washing. We had a big fight the other night and I was in tears. He was really good and today I've done a lot around the house. Someone please tell me it's not just me lacking motivation this far along in pregnancy? Also anyone got advice on how I can motivate myself. It's getting to the point where I'm worried about how good of a mum I'll be if I can't clean and look after a baby. I already suffer with anxiety and depression I am really scared of going thru PND