Hypermesis through out the day

Am

I have a question, I have HG but I’ve been given some good tablets that are helping when I wake up i feel great no sickness I take my tablet as soon as I get up and I’m fine untill about 8 hours later when my tablets due to be re taken and from about 2.30pm-8pm every night I am so sick! I don’t understand does anyone else have it at certain points of the day only?