Need advice - should I go to the ER?

Lately I've had a relapse of morning sickness and I started having severe shortness of breath. I saw my Dr Wednesday and he wanted to test me for a rare heart condition in pregnancy. I had an EKG and am supposed to have an echocardiogram sometime soon too. Since then I've only gotten sicker. When I lay down or try to sleep or even just sit idle, my head gets disoriented and I literally feel like I'm having a mini stroke or something. (I had a blood clot in my brain caused by birth control 6 years ago and it feels similar) I went to church today and I got very antsy and dizzy and started sweating buckets and I got that mini stroke feeling, my husband noticed and escorted me out and got ice water and I felt a little better after cooling down. Then I ate and got home and projectile vomited everything and then some. I have felt incredibly off all day and I'm increasingly getting more and more nervous. Part of the problem is that when I feel sick it's like sending me into little panic attacks that makes me desperate and terrified. There are times I seriously feel like something is wrong with me and I need help or I'll just keel over at work or something... but because there is nothing obviously wrong with me on the outside I'm reluctant to go to the ER. I don't want them to treat me badly and I really don't want iv' s because I always have a bad reaction to them and my veins blow out everytime. I need advice. I don't know if I should go to the ER tonight or wait until my Dr is in tomorrow. Problem is, I work and my Drs office doesn't even open until after I'm at work. I'm 18 weeks tomorrow btw.