Hi,
I am Donna (26 ) mom to David who is 21 months, I started temping when I was TTC him for pretty much the same reasons. I have an irregular cycle and I hated not knowing if I had O'd and then getting my hopes up every month.
I temp every morning at 4:30 am, My Dh gets up for work then Monday thru Friday so it just makes sense for me to just temp every morning at that time even if I don't have to. I have found it is more accurate.
I have to wake up severa times during the night as my son is still co sleeping and nursing. I am still able see my Ovulation pattern.
There is a way to adjust your temp using this link that was posted a while back
Basal Body Temperature Adjuster - WhenMyBaby
Good Luck