Whether a huge national debt indicates a bad economic situation in the country has been always a big question for me. Look at the list of top 5 countries with the highest external debt:
Wish I could find another thread talking about interest rates and inflation, and how much money's printed by a central bank, and how it's quite closely related to GDP, spending, and debt.
Now debt alone is a terrible factor to decide if the economic situations is bad. As someone else mentions above, what you produce economically has to play an important role as well. Especially if, as most economies try to do, the idea is to borrow so you can develop and build an economy that will pay back that debt and then some.
I can think of at least 1 country without external debt (Brunei) that has been very worried about its economy for the past few years since oil price dropped. Had they borrowed money -- and invested their income from oil in sovereign funds for example, instead of lavishing their reserves -- to develop and diversify their economy, they might not be in their problem today with stagnating industries and unemployment.