Whats the difference of being hypoglycemic or diabetic?

Are they the same thing? Is hypoglycemic mean you are in the early stages of being a diabetic? If I go without eating for more than 10 or so hours, I get dizzy, nervous and sometimes get hot or cold sweats. After eating something, I start to feel better but have a really bad headache. Someone told me my sugar may be dropping and I might be hypoglycemic. I can't find any info of what the difference in the two are. Thanks