How do i except runtime DLLs from this Anti DLL Injection code?

Hello everyone, 

I am going to make a anti dll injection in order to protect my game client,

but whenever i tried to use this code, some of runtime game dll will not be loaded, and the game will be crashed.

void AntiInject () 
{ 
   HANDLE hProc = FindWindow(0,"Gunz"); 
   while (TRUE) { 
      BlockAPI(hProc, "NTDLL.DLL", "LdrLoadDll"); 
      Sleep (100); 
   } 
} 
BOOLEAN BlockAPI (HANDLE hProcess, CHAR *libName, CHAR *apiName) 
{ 
   CHAR pRet[]={0xC3}; 
   HINSTANCE hLib = NULL; 
   VOID *pAddr = NULL; 
   BOOL bRet = FALSE; 
   DWORD dwRet = 0; 
   hLib = LoadLibrary (libName); 
   if (hLib) { 
       pAddr = (VOID*)GetProcAddress (hLib, apiName); 
       if (pAddr) { 
           if (WriteProcessMemory (hProcess, 
                            (LPVOID)pAddr, 
                            (LPVOID)pRet, 
                            sizeof (pRet), &dwRet )) { 
              if (dwRet) { 
                 bRet = TRUE; 
              } 
           } 
       } 
       FreeLibrary (hLib); 
   } 
   return bRet; 
}

So, my idea is to add dlls exceptions, but im really no ideas on it :(

Does anyone know how to edit the code to be worked? Or maybe there are other ways to anti dlls?

Thanks in advance! (Also please give me a code sample of your method, since im newbie on anti hacking :d)