Nausea returns at 18 weeks

I've not had any nausea or vomiting for 2 months until a couple days ago. The nausea returned. Yesterday I vomited twice...once when I woke up in the morning and then again a couple hours after eating dinner. I woke up in the middle of the night and had my hubby call the patient advisory nurse for me because although I've had off and on nausea/vomiting off and on throughout my pregnancy, I have not had it consistently throughout the day and night like I have the past few days. They told me to eat ice chips, sip on water and go back to bed because I haven't had any cramping or bleeding and I'm still urinating enough to not be dehydrated. They told me to go to convienient care in the morning but I don't need to go to the ER at this time. I have anxiety so I worry all the time and this is probably completely normal, but I like to seek advice from others going through pregnancy. Again I'm only 18 weeks and I can't feel baby movements yet so I'm just looking for reassurance that what I am going through is normal.