i get disconnected everytime

Macbook PRO 13 OS Mavericks😕

everytime i want to lay on my bed and put my laptop on my legs or tummy i get disconnected and i was wondering if it was a problem with the airport or something because i don't get this problem with my macbook white.

i thought that upgrade my IOS version may fix the problems but it didn't.

my wifi isn't the problema because i use my mac white, iphone and ipad normally. it just happen with the mac pro.

i may say that even if i place tha laptop in a table it gets disconnected and i have to open the network preferences in mac, click assist me, and then clic in diagnostics, follow like 2 or 3 steps, and finally my laptops says that everything is ok.

Note:

i have to do this at least 1 or 2 times per hour. 😠