I'm a 16 Year old girl now, when I was 3 I started getting bullied until I was 11, all because of me having autism. I was being mostly verbally bullied and sometimes physically, one time even being framed for something serious and it was horrible.

After I switched schools, I was not bullied anymore, in fact I made a lot of friends in the new school, even teachers felt impressed of me.

But despite being accepted and having a wonderful life for almost 5 years, I still can't forget about my past. I get dazed in certain moments, sometimes wanted to be alone, and I even cried once when thinking about it. It felt like a shadow is still haunting me and it never goes away, is it normal for people like me to feel that way sometimes?

Yes, it's normal. Our past doesn't really go away, it just goes to some back rooms in our minds as new experiences grab the front rooms. If we don't have full, content lives at the moment the past might fight to come back. Take a deep breath, think about it a bit, and try to identify what is going on in the present that is sad or lonely or missing something, because that is what matters now. A teacher frowned at something you wrote, or a friend walked right by you in the hall, or two kids giggled nearby and you aren't sure what about - we ALL have tiny events each day that can beat us down, and how much we let them depends on how secure we are in ourselves. You are still developing that inner security. Keep working on thinking out each sad moment.
All of life is an ongoing 'job' in this regard, for all of us. It's a matter of degree from one person to the next.

(Most of us here will insist that you didn't have autism because it doesn't just disappear. It's a diagnosis that gets handed out too often. I wish we know what might have been going on.)