What could cause a high hr (144) when standing but is somewhat relieved by laying (93) ? other symptoms nausea and severe headache. is 144 a concern that requires an er or will urgent care in the morning be able to treat it?

Your condition suggests an orthostatic tachycardia spectrum condition or POTS, either primary or secondary to a different medical condition, dehydration notorious among others. Other conditions cannot be ruled out and seeking timely medical attention would be appropriate.

See a doctor for an examination and differential diagnosis with treatment if required. Good L