It must be your code. The theme you’re using doesn’t work properly, and without a lot of work it would be difficult for someone to look at it and know all the things that need to be corrected.
By the default I meant the whole WordPress default install, with the Kubrick or Classic Theme. I think the Classic would be closer to what you are looking for. This is just my advice about the best thing to do for your blog. Delete everything and begin again.
Then once you have the Classic Theme working you can start to make small changes one at a time, checking everything as you go, and try not to change anything without knowing what the effect will be.
I think this is the best approach.