It's not a verb, it's an adjective: צריך, צריכה, צריכים, צריכות and in future/past you use the Hebrew "to be" להיות, as with other adjectives:
I needed = הייתי צריך/צריכה
She needed = היא היתה צריכה
He needed = הוא היה צריך
I will need = אהיה צריך/צריכה
Note: in future form there's another option, to use the root צ.ר.כ. with התפעל,
I will need = אצטרך
He will need = הוא יצטרך
Okay, that explains the irregularity. But I'm having a hard time understanding how "to need" something is an adjective. In the English translation, it's clearly a verb. "Needed" could be an adjective (e.g. "I am needed."), but that doesn't seem to be the literal translation here. How is the word mutated? It seems to be done with respect to the needer, not the needee, yes? Where is the verb in the sentence? Is it an implicit "to be"?
You can think of it as "in need of", it sort of describes a state rather than an action. In inflections, it behaves just like a regular adjective. For example, comparison between שמח and צריך in both languages:
I'm happy = אני שמח/שמחה ; I need = אני צריך/צריכה
We're happy = אנחנו שמחים/שמחות ; We need = אנחנו צריכים/צריכות
I was happy = הייתי שמח/שמחה ; I needed = הייתי צריך/צריכה
He will be happy = הוא יהיה שמח ; He will need = הוא יהיה צריך
The inflection, as with all adjectives, is with regard to gender and plurality only, ignoring whether it's first/second/third person.
There are some Hebrew-speakers, such as Yemenites, who pronounce the ח differently than the כ, by slightly constricting the muscles in the throat as they exhale. (I believe it's a common sound in the Arabic language, Majsburk, so I wouldn't be surprised if your comment about ك and خ was accurate.) At 4 minutes into this vid, he demonstrates the ח sound I'm talking about- https://www.youtube.com/watch?v=O7RIAPosxEI. Good luck :)
In the past, radio and television personalities were required to pronounce the ח differently. This rule has been gone in the past 20 years.
The Talmud names three cities where the distinction in sounds is not made, so residents of those cities are disqualified from the post of high priest.
Just to reiterate and add to the already great answers, the sound used by a minority of speakers is a "voiceless pharyngeal fricative". https://en.wikipedia.org/wiki/Voiceless_pharyngeal_fricative https://en.wikipedia.org/wiki/Modern_Hebrew_phonology
Here's what linguist Randall Buth has to say (from his "Hebrew Audio Pronunciations", published by Logos Bible Software):
"ח חֵית ḥ ḥêṯ This is the voiceless pharyngeal fricative in Masoretic Hebrew and a minority of Modern Israeli Hebrew dialects. It sounds like the Arabic letter ح. E.g. חָרָשׁ ["craftsman"]. Most Modern Israeli Hebrew speakers do not distinguish between this sound and the voiceless velar fricative כ."
I must admit that I could not survive the movie farther than ט. In modern Hebrew ח,כ have the same sound and ק,כ have the same sound. In some communities that came from Arab cultures כ is pronounced as the arabic letter خ while ח is pronounced as the same letter without the dot. Likewise dotted כ is pronounced as ك and ק is pronounced as the other "kaf".
When you is the subject, it's אתה (ah-TA) if the "you" who you're describing is male or את (Aht) if it's female. There's also אתם and אתן for plurals.
If it's an object you need the את (et) word that precedes direct objects. And you get a contracted word because את + אתה = אותך (Oht-cha) and similarly אותך (oht-ach), אתכם (eht-chem) and on occasion אתכן (eht-chen)