Don't take so much Oreo biscuits then?

Try Dulcolax. Available from pharmacies.

Side effects may include stomach pain or diarrhea but that depends on the person. Some people have no side effects, some get diarrhea etc.

Senna is a stimulant laxative. It forces the muscles of your intestines
and colon to go into spasms, so pushes the stools out.

If you take it chronically, your colon is going to become dependent
on it, i.e. addicted, and so will become lazy sooner or later.
Try eating at least one purple-type dragonfruit a day.

You will be sure to run to the toilet more often with softer stolls.
The downside will be they will appear dark and purplish
Order some artichoke tablets from here. Take one daily.
Your stools will be more, softer and also yellowish.

http://www.healthspan.co.uk/products/artichoke-extract
Artichoke makes your gallballer secrete more bile, which in turn
causes more yellowish stools.

It will also reduce flatulence or bloating.
The cynarin in artichoke is also a powerful cancer fighter, so if you
take it regularly, you will be unlikely to get liver or colon cancer.
Here too :

http://www.iherb.com/Nature-s-Way-Artichok...0-Capsules/1824
I've taken both of the above before. Still have a couple more capsules
of Nature's Way.

No, it's not normal.  Sounds like a visit to the doctor is overdue.  Stop asking for advices here; could be more serious than constipation.

How old are you?

if it's serious and the problem is prolonged better be safe than sorry la brother. I myself take coffee everyday to and have no problem with my bowel movements, but if u find your case is genuinely strange, you will need doctor's help for expert opinion or get yourself analysed better medically by them.

wow really? wtf? u have allergic reaction zit? try consult doctor le, like srsly allergy scratch test or something better than just making a guess of how to manage ur probs.

Yes!
Only live probiotics will work
You can try
Live, refridgerated probiotics supplements,  not room temperature supplements
Keffir yoghurt
Fermented foods like Kimchi and Saurkraut

And take Psillium husk powder for soluble and insoluble fibre

I tried the Lacto 5 from guardian and they did nothing for me, 
but they were the ones of the shelf...

Go for probiotics that need refrigeration,  my local Farmasi has
probiotics for sale in a refridgerator in store...
the ones you can buy on the store shelf wont be much good...

It takes a long time to build up the good bacteria in the gut,  so you will have to take probiotics as well as fermented foods...

Btw fermented foods are probiotics too and they are very cheap to buy...

Good luck!