I have prbs in raising & sustaintity

You should see a doctor to check if there is any medical cause, and to find out if any of the many drugs available will be suitable for you. It could be extremely dangerous to purchase these drugs online, without consulting a professional first.

I think it is too thin and short

I think your ‘big problem’ is almost certainly in your mind, ejtehadi.

Just as men come in a wide range of shapes and sizes - so do woman. I can assure you that there are many, many woman in the world who will not reject a man just because he does not have a monster penis!

give me a suggestion so that i can make it bigger

Except for radical and insanely expensive surgery, it’s basically impossible. Don’t waste your money on fake drugs or useless methods which are only designed to rip off uninformed and insecure people.