Headache, weakness, upset stomach,

My son 8 year old is complaining of headache on and off since last 1 week. 3 days later he vommitted all he ate and since 1 day later(last 3 days) saying that he too weak to play pr sit and eat his food. Also says feeling vomitting sensation, though doesnt vomit. Also complains of stomach being upset but no loose motion though going for potty 3 times a day since few days, normal days he goes only once. What it could be. Due to covid not willing to visit clinics until these symptoms need physical evaluation. Please advise any medicine which can help, else suggest which type of doctor we should go to and whether physical checkup seems necessary. We didnt have any contact with anyone since weeks, so covid shall not be case still please suggest if feel we shall get him tested. Thank you.