There are elements of this post that I can really sympathise with, OP.
I'm also 32 weeks pregnant (congrats, by the way!) and have two dogs - one of them has very recently decided they only like to pee on the concrete just outside our back door. I use a spray bottle filled with 2 parts white vinegar and one part water daily which helps with the smell and saturate the concrete with a vinegar and water mixture every now and again, scrub the concrete and let it dry naturally we now don't have any smell of dog pee (we're also working on retraining the dog, but she's old and a bit of a slow learner!) - you can also buy cleaner that works really well on concrete - Pro-Kleen Kennel is a favourite with other people that have this issue that I know (It's sold on Amazon).
In the long term, it sounds like the dog needs a lot more exercise, to be honest - I know it can be really hard to be motivated to do it, especially when it's raining or whatever, but 30 minutes is not enough of a walk for most breeds. If a dog is well exercised it will cope better with being left alone, but realistically, you need to consider if your home is the best place for the dog. No matter how much you love the puppy, if your home is not the best place for it, you need to seriously consider rehoming, OR, changing your lifestyle so that you are the best place for your dog - I.E - walking more regularly, having someone come in to walk the dog regularly etc. I can understand that when you're really lonely the thought of giving up a companion can be really terrifying, but there are other ways to tackle loneliness and keeping a dog in an unsuitable home because of your loneliness just isn't fair.
As for the house issues - I think you need to chat to DH and explain that you are not solely responsible for the housework, and that whilst you acknowledge that you need to do more, you also feel that he needs to do his fair share, too. A rota might really help with this - write a list of what needs doing in each room, and how often, and then decide who will do what. Rotate jobs/rooms if needed, or, split them into specific jobs so you each know exactly what you're responsible for.
When we first moved into our current house I struggled to find the motivation to clean it constantly because I felt similarly to you about a lack of pride/joy at living in the house (it was a REAL fixer-upper, still is - and I HATED it) so I often let stuff that wasn't as obvious slide, which made the house messier, which made me feel worse etc etc. But I found that by doing a really deep clean/tidy/organise of one room helped me to regain my sense of pride and happiness and we both felt a lot more motivated to maintain that room (we also got rid of a lot of clutter that helped, too). DH and I cleaned, organised and tidied each room in turn like this together (usually on one of the few days we get to see each other- we, too, are currently not seeing each other much due to work) and we both felt a lot better for it. Is this something you could suggest? Perhaps you could paint the rooms or rearrange the furniture to make the room feel new and fresh? That might help you to feel more motivated to keep it well maintained.