In the morning I never know if I'm still on my period or not?

Okay so I am still in an irregular scedual with my period. I get it every month. sometimes 2 times a month, and i have a regular flow. I am using tampons but at night i wear a pad because i sleep in. Okay so, unless it is around 10-12 blood never gets on the pad. Like before those times there is no blood. And when I wipe - nothing. This is really hard for during school because I don't want to wear pads because you can smell them, i feel like i'm wearing a diaper and everyone can see, blood is gonna get on my pants, it is loud to take off and open a new one, etc. Why does it do this & what should I do? Also, I keep forgetting to keep a calender of when I get my period because my calender is one of those erasable kind. I put T.O.M in my calender on my ipod but i forget to extend the day - if that makes sense. What should i do because i dont wanna ruin my new panties compared to my period panties ;D I usually get my period the beginning of the month (i've had it the 1-5 or 7-whatever) or i get it at the end (19 or 20s) Please help. I know this is scattered and a fail at writing.