My mind seems hyperactive

I don't know if this is normal... But, I'm like that most of the time.. even can't sleep rightaway cos my mind is always busy, thinking about random things.. even when im walking or in class. I understand how you can find it so irritating =/

I've been diagnosed with what they call "adult ADD", essentially ADHD without the hyperactivity. I think the correct term is ADHD-PI (primarily inattentive) or something like that.

Even though I don't exhibit any physical hyperactivity, quite the opposite actually, I do have a hyperactive brain. I constantly have hundreds of thoughts just whizzing by uncontrollably, which makes it very very hard to stay focused on anything for more than a few minutes/seconds. It has improved slightly with medication but it's still pretty overwhelming at times.

Like someone mentioned before most people experience this from time to time, usually when they're stressed about something or tired. Your frontal-lobe (correct me if I'm wrong) has a filter-function to sort out the unnecessary "junk" and help you focus on what's important at the moment, when this process malfunctions for whatever reason you get flooded with brain-chatter constantly.

Some people aren't that bothered by it and some even enjoy it, but others, like myself, need help with controlling it as it's affecting my academic performance and my social life.

I'm not entirely convinced that people with this problem all have ADHD/ADD, but instead different brain-structures with both pro's and con's. Just like we have different personalities.

I believe that ADHD is grossly over-diagnosed, which is really a shame since this has lead people to believe it's just a label for misbehaving kids or slow learners etc. Which in turn makes it difficult for someone really suffering from it to be taken seriously by friends and family and colleagues.

Alright, sorry about the rant, if you feel that this is bothering you to a point where it affects your ability to reach your goals, whatever they may be, I suggest you see a psychiatrist to discuss your symptoms and then go through a neuropsychiatric evaluation to determine if you do indeed have some sort of attention-deficit disorder.

There's plenty of treatment options available, and they do not all include stimulants.

It sounds quite possible that you may have adhd (Attention Deficit Hyperactivity Disorder)

Symtoms include
* difficulty paying attention to details and tendency to make careless mistakes in school or other activities; producing work that is often messy and careless
* easily distracted by irrelevant stimuli and frequently interrupting ongoing tasks to attend to trivial noises or events that are usually ignored by others
* inability to sustain attention on tasks or activities
* difficulty finishing schoolwork or paperwork or performing tasks that require concentration
* frequent shifts from one uncompleted activity to another
* procrastination
* disorganized work habits
* forgetfulness in daily activities (for example, missing appointments, forgetting to bring lunch)
* failure to complete tasks such as homework or chores
* frequent shifts in conversation, not listening to others, not keeping one's mind on conversations, and not following details or rules of activities in social situations

See more at: http://www.webmd.com/add-adhd/guide/adhd-symptoms

Do the thoughts have a theme? Even a loose one? Or is it completely random?
If you think it's productive, if it's helping you have great ideas and positive realizations, then great. Otherwise it might be a mild case of OCD combined with ADD and there is benign treatment for that.

Everybody jumps around topics, and occasionally has been kept up by ruminating, but if you feel its become too much talk to your family doctor.

This is completely normal. It happens to me all the time. I almost always have twentythousand things on my mind. I can't ever focus on one thing.
I normally believe that i have this because i'm really stressed out about something.
What i normally do to try and calm my mind down is just lay down listen to calm music and blank out your mind of everything.
Sorry if it's not much help.