When do I start timing?

So I have been feeling “crampy” all day. I am 2 cm dilated, found out 2 days ago. I have a high pain tolerance so I don’t know when I should start timing? I am getting cramps but they are like period cramps. Will contractions make me hurl over in pain? Or should I start timing these “cramps” even if they don’t hurt as bad as i am expecting them to? I have no idea what to expect