Could i need *three* root canals?

It's possible: I'm not clear on your question. We need more information. A patient could require root canal therapy on more than one tooth. There is not limit. A tooth can have one, two, three or four canals (and possibly more) depending upon the individual tooth.

Get 2nd opinion: It's hard for me to answer that question without seeing your radiographs. Do you have pain? Do you have discomfort to hot/cold/chewing? Trouble sleeping at night? If you were diagnosed as needing 3 root canals, you can always get a second opinion from another dentist.