かぜを引いているんだ。

wind; breeze; draught; draft; manner; behaviour; behavior; cold; influenza

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to pull; to draw (attention, etc.); to attract (interest, etc.); to draw back; to draw (a card); to draw (plan, line, etc.); to catch (cold); to play (string instr.); to look up (e.g. dictionary); to consult; to haul; to pull (vehicles); to subtract; to ebb; to fade; to descend (from); to inherit (a characteristic); to quote; to raise (as evidence); to lay (a cable); to draw (a cable)

yes; yeah; uh huh; negative verb ending used in informal speech (abbr. of negative verb ending "nu"); abbr. of particle "no"; abbr. of particle "ni" (used especially when it precedes the verb "naru")

be; is; indicates past or completed action; indicates light imperative