My Head is Full

Japanese class has been getting more and more difficult. I do my best, but it is really hard.  This week, we had an exercise using to ki as a connector to make two sentences into one.  The example was something like: He eats rice. He uses chopsticks. When he eats rice, he uses chopsticks. Gohan o taberu to ki, hashi o tsukaimasu.

We go around the table taking turns making sentences from little cartoon pictures.  I was happy when I saw the picture for my turn because I thought I knew what to say. The picture showed a woman with lines coming out of her head, putting a pill in her mouth and holding a glass of water.  I was sure it meant “Her head hurts. She takes medicine.  When her head hurts, she takes medicine.”  I said “Atama ga ippai to ki, kusuri o nomimasu”.  My teacher was laughing because I said when her head is full, she takes medicine. What I should have said was “Atama ga itai to ki, kusuri o nomimasu.”  (Ippai - full, Itai - painful)

My head is full.  Is there medicine for that?