The past perfect takes a form of HAVE (have, has, or had) + a past participle (a word ending in -ed or -en); e.g., have eaten, has gone, had been. Our example sentence
I had my hair cut doesn't have a past participle, so the verb isn't past perfect.
Subjunctive is a mood. It's used for hypothetical and contrary to fact situations. There's a great deal written about it online. Try
§ 61. subjunctive. 1. Grammar. The American Heritage Book of English Usage. 1996
Does that help?