。
She told me I should see a doctor.
Literal
She [topic-は] me [to-に] doctor [from-に] examine-receive [should-べきだ] [quotative-と] said.
A medically-themed sentence with three things going on. (1) 医者に診てもらう — literally 'have a doctor examine (me)' — uses the benefactive ~てもらう, where the doer (医者) is marked with に. This is the standard idiom for 'see a doctor / get medical treatment' in Japanese, which conceptualizes the act as 'receiving the favor of being examined' rather than the more agentive English 'see a doctor.' (2) 診る (specifically 'examine medically') is distinguished in writing from 見る ('see, look') — though both read みる. (3) ~べきだ ('should') gives the advice firmness. Using polite past 言いました (vs the abrupt と言った) softens the report register.