Lamictal with Viibryd for irritability?

So my psychiatrist prescribed me Lamictal today. I always research the meds afterward. So I find out it's for bipolar depression which I don't have since I never have intense mood changes. I never have mood "highs" just very intense mood "lows". I've been diagnosed with clinical depression along with several anxiety disorders and ADHD. But anyway, he prescribed me this since I've been really irritable. It seems to happen after I take Viibryd which I had recently started. It could be that I forget to take them every day or I can't always take it with food. Should I simply take a new antidepressant or is this because I am not taking it correctly? Should I take the Lamictal? Also, note that this man thought letting me take Clonazepam up to three times a day as needed would be a fantastic idea.

I trust my doctor so if he tells me to take a certain drug, I take it and then deal with anything negative immediately. Has Lamictal caused any side effects? I am not sure how long it takes to work, but I do take it at a high dose of 300mg.