Hi, and welcome aboard
Much of the confusion regarding the use of adjectives vs. adverbs (i.e. different vs differently) comes from the fact that the user/speaker is unable to distinguish what the word modifies
Consider this example:
The fish tastes different/differently today
Remember that adverbs (such as differently) modify verbs, while adjectives (such as different) modify nouns. In the example above, if you use an adverb, the sentence becomes:
The fist tastes differently today
Although not ungrammatical, it is semantically weird, since it means "the fish uses its sense of taste in a very weird way", or something like that!
Instead, The fish tastes different today makes use of the adjective (different) to modify fish, which is what we're really after here.
So, back to "don't take it personally/personal", although "Don't take it personal" is used (124.000 hits in Google), the correct way to say it is "Don't take it personally". Personally modifies the verb take.