The idiomatic expression get hold of means to obtain, pick up, or grab, both literally and figuratively; it may sometimes appear with differing verbs, such as grab, take, and have, but the meaning remains the same.
Avoid the colloquial American variants get a hold of and get ahold of, which remain far less common in writing than the standard phrase. Prefer Get hold of yourself to Get a hold of yourself or Get ahold of yourself.