Maybe both. Aside from diabetes, there are other less common reasons to spill glucose in the urine. However, the bladder collects urine over several hours at which time a blood sugar may have been transiently elevated. Therefore, even if a blood sugar is normal at one point in time, urine represents hours of time.
Neither. A normal blood test rules out diabetes. There are other reasons for sugar in the urine besides diabetes.
It means high bs. The presence of glucose in urine can only be explained by high bs in the blood that exceeds renal capacity for glucose reabsorption (which is around 180mg/dl). Having said that, you should seek an endocrine evaluation to find out your bs trends and if you are at risk for diabetes. On final note, renal disease can also lead to leaky kidneys which loss of electrolytes, Amino Acids etc.