Your doctor will be the one who can answer such a question best. In fact, if you are suicidal he/she should know, especially as you begin a new medication, regardless of the medication or dose.

I have found Lamictal to be activating for me in the past. When depressed, it did pull me out of the depression, but not at 25 mg. The lowest helpful dose for me was 75 mg. At 25 mg it was still like not having taken it at all.

I did have a period when I was suicidal on Lamictal and Abilify, but only after both giving me weeks of delightful stability, followed by elated hypomania, and then eventually full blown mania with mixed features. It was the mania with mixed features that made me a risk to myself. Not pure depression. At that time I was on 300 mg of Lamictal and I forget how much Abilify. I think Abilify was also activating for me.