Note: "if you ever experience a situation like that again" is not a sentence - it is a phrase. A complete sentence must have a subject and a predicate (the predicate contains the verb). Usually, when you begin a sentence with "If ..", you must complete it with a sentence beginning with "then". Example: "If it rains tomorrow, then I will not go to the park." Of course, most people do not include the word "then", so the sentence becomes, "If it rains tomorrow, I will not go to the park." This is also grammatically correct.