Quitting my job and dealing with anxiety

I am 26 and just graduated from college and began working for Target. I worked there for about 2 months but one day I started thinking about the past and the future. There is something I need to accomplish in my life and I want to find it. At Target, I wasn't earning a lot, my schedule was all over the place, I was always tired, and I wasn't earning a lot of money. I love the company though because it was my first job and part of the reason I wanted to move on was because they opened my eyes to the many possibilities. I am going through a lot of stress and self doubt at this point in my life. I know I gave excellent customer service and I made sure everything looked nice and neat. I just felt that I was missing on a lot of opportunities out there and I needed to leave in order to accomplish my goals. So I called and told an assistant manager of the store that I was calling to resign. She was no help but told me to give them a 2 weeks notice so that I leave on good terms with the company. At this point in time, I am completely stressed because my schedule is not stable and I am not getting anywhere fast and I need to do something quick. They had me going whenever they wanted, making push all the heaviest things, and I was afraid I was going to get hurt because I was tired all the time. That said, I decided to go in and talk to them face to face. I talked to supervisor who I got to know as a friend and I told him everything and what I wanted to do. He understood because they know I have a Bachelors degree and that it brings a lot of possibilities for me in the future. At the same time, he told me he was working to get his education and he also wants to pursue his goals. He made me understand that Target is a forgiving company that will back me up. At the same time, though, I am replaceable. After that, I talked to human resources and quit on the spot. I didn't give the two weeks notice because when I went in to talk it was pretty much all or nothing. The human resource manager told that in he future to give a two weeks notice and good luck. And that was it. I went out. I really didn't want to risk getting hurt and couldn't take the stress anymore. I felt terrible after I left. I am second guessing myself a lot because what if now a potential employer won't recruit me because I quit and din't give a two weeks notice. I liked the job, but at the same time it wasn't getting me anywhere. When I got home, I opened my email and saw that another company wants to interview me. This seems like a better offer and I want to pursue it. However, I am afraid that by me quitting on the spot will have consequences and that's what I am afraid of. I can't sleep because of it and don't know what to do. What do you think?

Well, you could say, if asked in the interview, that you had to quit your job because of physical problems. You went to the doctor because you were feeling physical pain, they told you to take some rest and you decided that job was not good for your average health.
Above all, do not worry about that. You don't have to be afraid of quitting a job. In fact, I quit one recently on the spot like you, because it was a "business sect" (well, directly translated from what we call it here in Spain "secta empresarial"). 10 hours a day, no base wage, pyramidal structure in which the 60% of my sales were retained by my boss, with half-truth's, stress and bad treatment towards employees. Should I give the month notice (in my case) before I left? No way.
Just don't be afraid of what you have done. You haven't quit your job because you're lazy or something. You have quit it because of your health, an important reason.
So sleep well, you're going to need to be fresh for your life =)