Learn Spanish (Latin America): Hoy estás débil. Hay que tomar una pastilla. - You are weak today. You have to take a pill.

Hay que is an impersonal phrase that means 'one must' or 'it is necessary to'. While the English translation says 'You have to', the Spanish sentence is phrased as a general medical recommendation rather than a personal command. If you wanted to use the verb from this lesson to give direct personal advice, you would say Debes tomar una pastilla (You must take a pill).

Why use estás instead of eres with débil?

The verb estar is used for temporary states or conditions. Because the person is only feeling weak today (hoy), estás is the perfect fit. If you said eres débil, using the verb ser, it would mean the person is generally a weak individual as a permanent personality trait!

I thought tomar meant 'to drink'. Why is it used here for taking a pill?

You are right that tomar is often used for drinking beverages, like tomar agua. However, it is also the standard verb in Spanish for consuming medicine or swallowing pills. You wouldn't use other 'take' verbs like llevar or agarrar for medicine.