Yep, you definitely need to keep shampooing your hair.
There’s a growing group of people who have stopped using shampoo. Some go cold turkey, some use only conditioner (also called co-washing), and even others stick with DIY solutions. But before you jump on the no-poo bandwagon, watch this video from The American Chemical Society. It explains the importance of researching home remedies (oil and vinegar, for example, can be more damaging than helpful) and dispels the myth that your hair stops getting greasy after you kick shampoo (turns out your body still produces oil).