Toddler sleep

Any advice please… My son will be 3 in November & has always slept really well with just the occasional blip. (Usually 7/7.30 - 7/7.30) But over the past week or so he has been getting really upset at bedtime & taking 30mins+ to get to sleep. He’s also started waking at 5.30 & getting out of bed saying he doesn’t like it in bed or he’s scared of the dark even though there’s a light on. He is still napping, the time varies everyday depending on when he woke up, & it’s usually for an hour. He didn’t nap one day last week & was hysterical by 5pm. I’m so drained by it & just don’t know what to do!