possible screw up?

i just finished brewing my first beer ever. i was doing a pale ale. i did everything the instructions said and my O.G. which is specific gravity? is at 1.020. what does this mean is my beer gonna be water or what? i dont know much about brewing, any ideas would help. i started steeping at 160 degrees and it did drop down to 148 for maybe 5 mins before i got it back up to 155.i added the DME and half the hops after steeping and had a low boil going stirring every 5 mins for 50 mins. added some irish moss and the rest of the hops and boiled for another 6 mins. did i do something wrong in the process?

thanks for any advice

What is the recipe? That is a very low OG are you sure your hydrometer works?

As Cave said, "what is the recipe?" If you were doing extract only your OG should not differ much from what was calculated.

You might be dealing with a bad hydrometer or more likely a difference in density because your wort sank to the bottom of the fermenter after topping off with water. How did you take your sample?

Wow, that is low for an OG. 1st, did you let the wort cool before taking a reading? And 2nd, what is the recipe? How much DME and specialty grains did you add?