Weak Body...?

Hi mummies! I am coming 24weeks in days time, i actually realise that i am getting even weaker and i get tired easily for the past 1 1/2months.. Recently i went out with my mother and walked for about 20mins, i feel like collapsing as my body felt weak and was lucky to get support by grabbing a shelve. A week ago, i was getting ready to head out with my partner and also felt the same. Today, i feel rlly weak and tired.. Just the same way as i felt those 2 times, why is that so? Is it normal because its my first pregnancy? I am not working, i am staying with my parent and doesn't do any housework except for cleaning my room.😭 i kinda hate this kind of feels that my body is experiencing now..