Worried and headed are not past tense forms in your sentences, but they can be that in other contexts. Am is present tense and worried and headed are past participles even though they don't differ from past tense forms in appearance. Technically, they are verb forms but they are actually used in such a way that they resemble adjectives in meaning.
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Equilibrium8What would make it a past participle and not an adjective?It can of course be called an adjective. It is, however, a form of the verb to tire, and therefore the term "past participle" is also justified.