So sorry to hear you're having a hard time.
I'm 29 weeks also, and had the same evil sickness for 5 months. Not too bad at the moment, but I have awful SPD, and I just don't do pregnancy well.
I've never enjoyed pregnancy (on my third now) and yes, I understand feeling guilty about that. Have a chat with your midwife maybe, especially with the anxiety you've been feeling.
I've had impetigo once too, and it's horrid. Having it pregnant, even worse, so take it easy on yourself.
I do think it's a shock when pregnancy is so hard. I think you're supposed to enjoy it, bloom, never look better etc, but for many of us, it can be hell.
The only thing that keeps me going, is taking each week at a time (each day when it was really bad!) - and you're in the last trimester! Not long to go now 
Don't beat yourself up for not feeling on top of the world. Just because you're having a hard time with the pregnancy, doesn't mean the baby isn't very much wanted. Try to focus on anything positive, and can you chat with DH about it? It's so nice to share how you're feeling, even just to get it off your chest. Anyone else you can confide in?
Take care x