Melody - free yourself sweetie.
Once you realise that sleeping habits have very little to do with your parenting and a lot to do with how your bub just is you will feel much better. I have been through it too and tried a lot of things. Nothing really worked except for time. But when I realised it wasn't cos I was a bad parent then I relaxed a lot more and it all became easier. 6 months is still young. The best thing you can do is get some partner or family support so you can either alternate nights or get some more sleep during the day. Don't think you have to do it all yourself.
You are going a great job I am sure.
Big hugs