Most people doing Ph.D in natural science go through this phase. If I were you, before quitting in a whim, I'd have a solid back up plan. You can definitely get master's before you quit. It explains in your academic handbook what entails for you to get your master's.

However, the more important question is what do you envision doing if you quit Ph.D. today? Not that the prospect of Ph.D holder in landing a high-paying job is any higher, but in the current economic climate, you would be stressed to get a job you like. Again, if you've made up your mind to quit, I'd make it a one year plan. During that one year plan, I'd do informational interviews, develop networking for jobs, go to career fairs, reach out to "head hunters"or alternatively explore other academic degree you might be seeking.

To understand how bad the job market is, you'll have to go to some career fairs of pharmaceuticals/industries. you'll see people in their 50's being laid off left and right. You'll have to compete with these people who have experience more than your age. sorry to paint such a gloomy picture. But on the bright side, even if you start out at the very bottom, by the time you gain four -five year experience in an industry, you'll be getting paid much more than a person with a fresh Ph.D degree. :)

But rest assured you're not alone in this. Most students that enroll in Ph.Ds really don't know what they have signed up for.

"The worst thing about pursuing Ph.d is, you're 35 & you don't make a dime!"
- A Ph.d in IVF :)

@ guy tensed, I believe you have a masters before you enrolled to PhD. Is it true that you wanna get another masters for ur time enrolled in phd? Is that possible in US?
I am here in Korea and at the end of my third yr of phd. I just want to quit real bad. I am just scared that I will be loosing 3 yrs of my life if I quit now.
If these 3 yrs of my life can somehow be my experience in research or be a masters equivalent, I would quit right away.

@snurp You are so correct in saying that we need a exit strategy and need to make it firm and realistic. This may just take 6 months.

@casino I am a fine example of that.
35 yrs, family to take care, no other job, no dime in my pocket, no significant work experience in past, no industrial exposure. Life is doomed.