take care my dear friend!!! = T-hlla f rask, sadiqi l3ziz.
[I didn’t use the common word “sa7bi” for friend, as it may refer to a bf]
don’t forget arianna !!! = Ma tnsash Arianna.
i’ll miss you so much = Ghadi ntw77shk bzzaf.
call me when you want = Ttasl biyya mlli tbghi.
i love you ((((translate that for friend not for boyfriend;P))) – To avoid making it sound like a romantic I-love-you, I suggest: Rak 3ziz 3liyya, which means “you are dear to me”.