Why is my hair still very thin after five and half months of hair transplant?

You will lose your transplanted hair as well as some of your native hair weeks after surgery.  You may look worse before it starts to look better. It may take 6 to 12 months to see the results of a hair transplant surgery.  It is always a good idea to follow up with your doctor for a recheck if you have concerns.

Your transplanted follicles will take up to a year to start growing.  Please don't be concerned with your density now.  Assuming you had enough grafts to make a difference, you will see better results with time.

I generally don't evaluate the end result before six months because I have seen patients who start showing their full density after months 6 to 8 at times.   I cannot make a comment about the gaps and what density you should expect.  It all has to do with the technique and dense packing that you received.

 A Hair transplant will not get you to 100% density.  It should increase density and improve on a balding head.  So it depends on how dense you are now and before the procedure. Also, it can take 18 months so its still very early to even judge at this point. 

and my hair is still thin. Wait it out until you reach 8 months and then you will know if this is the way it will be. 5 months is too early.

It is still too early at five months to expect too much growth. At this point you may have about thirty percent growth. It will increase by ten percent each month until twelve months post op.