For 4 days I’ve had a headache, then accompanied by heart palpitations. Seen at the ER, and they said bloodwork normal, heart palpitations normal (been diagnosed in past). Now a red rash shaped in a ring appeared on my stomach tonight. Lyme disease??

Red rash ring. Please return to your doctor and show him/her the rash. Blood testing for Lyme is not always accurate but if clinically indicated, the doc MAY start you on an antibiotic. Lyme produces all sorts of symptoms. Whatever is going on, find the diagnosis and treatment.
Second opinions can help. Peace and good health.