Yes , You can do both in Manual but it wont be accruate, 

For Performance Testing , You can start with your 
application and check how much time take for the sub pages 
( eg. Search , and Adding new data or while submitting the 
form etc...) , they may have the requirement for Session 
Handling , so u have to make sure that all the search 
(reteriving from huge database ) within the session time it 
has to dispaly the data.

For Load Testing , You can check with same data / 
application run by more than 5 to 6 system at a same time 
and check how long it will take to reterive the data from 
database.( check with all popup and search screen ).