People may or may not have the sysmptoms you're describing when they quit smoking.
One way to combat the concentration/dizzy feeling is to eat smaller, more frequent meals to keep the blood sugar up.
I'm not sure what method you use to quit, example patch, gum cold turkey etc., but if you're using an NRT, it is more important to use the advice given above, because nicotine still might be placing havoc on the body.
When you smoked, nicotine caused an interaction that caused you're body to release it's own stored fats(sugars). This raised the blood sugar.
So now that you're not smoking, nicotine is not automatically doing this, but from years of smoking we forget that we need to constantly feed the body with energy. Smoking hijacked on how we recognized needs.
Being hungry, thirsty, tired, etc. often got confused with a need for a cigarette.
As far sleep. Sleep disturbances are not that uncommon when quitting. I was a bit tired for a while.
If you're having trouble sleeping. You may want to check your caffeine intake if you drink caffeinated beverages.
Nicotine hampered your body's ability to absorb and utilize caffeine. If you're still drinking caffeinated products. Be aware that it now only takes approx. 1/2 the amount to get the same effect.
Cutting Caffeine when quitting eases a lot of quitting symptoms.
Your tight throat could be from a few things. It sounds like stress, but be aware that also, cigarettes had an ingredient that caused the smoker's airways to open more so as to be able to absorb more nicotine, but if your tight throat was from that. I would think that it would have been back to normal by now.
Another factor is smoker's are notorious for shallow breathing. Their only real deep breathing comes from inhaling cigarette smoke.
One of the best things that a new quitter can do, it to practice deep breathing. 1. it will help relax you. and 2. it will help you breathe more effiecently in every day life. 3. it will improve your circulation.
Google yoga breathing techniques and you will find a lot of helpful breathing exercises that you can practice anywhere at any time throughout the day.
Eric