症 (Kanji for symptom)

Onyomi

SHOU

You're SHOWING symptoms of the sickness, so you're correct to say you have it!

XXX症(XXXしょう)	XXX - disease ★★★☆☆ SUF SUFFIX meaning XXX-disease. Only used in the proper names of specific diseases, in contrast to 病気（びょうき）, which means sick in general.
花粉症(かふんしょう)	hay fever ★★☆☆☆ 花 (flower) + 粉 (powder) + 症 (symptom) = 花粉症 (hay fever)
XXX 恐怖症(きょうふしょう)	xxx- phobia ★☆☆☆☆ SUF 恐怖 (super duper terror) + 症 (symptom) = 恐怖症 (xxx- phobia)
症状(しょうじょう)	symptom ☆☆☆☆☆ 症 (symptom) + 状 (circumstance) = 症状 (symptom) symptom of a disease