Immediate home care for high blood pressure (180)? Medication already taken.

Epsom salts. Take epsom salt - the one you can take orally mix 1 tablespoon with water - add lemon juice if you want to mask the taste keep drinking this every half hour until blood pressure comes down - this has magnesium make you have diarrhea but will relax the blood vessel wall and drop pressure quicker.
Yes. Yes, it is and you should have gone to the hospital. You need to see your doctor asap. Untreated high blood pressure can cause damage to your organs especially your kidneys, and are more likely to have a stroke. Avoid caffeine, smoking, tobacco products, decongestant medications and stress.