Woke up with very bad dizziness... All day dizziness, nausea, headache, really bad neck pain at the back of neck. Dizziness gets worse lying down?

Concerning. In an otherwise healthy 26-year-old, the description is concerning for meningitis (or several other causes of severe/life-threatening headache). If this new headache with dizziness is ongoing without any abatement or worsening throughout the day, then there should be a low threshold for seeking emergency evaluation.