Categories are not showing

Hello, I have the following problem:
I loged to my web site, and my cart (module) had a couple of items in it. I tried to add new items to the cart (the cart was updated) and clicked on "continue to checkout" in a popup window. Then, i was redirected to a main category page (root), with the description text, but with no visible categories. It happenes all the time.

Another problem i have:
I configured 2 delivery methods: self pickup and a delivery (min. of 150$). i was testing the store, and i saw that sometimes, only "self pickup" displayed, although the payment amount was more than 150$.

Pardon for my English and i hope that you could help me