Translation:My luggage contains two large suitcases and a small one.
Ovidiu is right! Actually the word "mic" is polysemantic... If one just says "un mic", it means "a burger" (in Romania "mic" - pl. mici - are very popular small cilindrical minced meat burgers)
Another distinction to be made here:
unu, unul (f. una) - indefinite pronoun
un, o - indefinite article
unu - numeral