Lamictal didn't help me at all, but didn't cause mood swings, either, or make it much harder to control my behavior. 50 mg is not normally considered a clinical dose - 100 mg is the lowest clinical dose BUT it may be that is what is the lowest dose for bipolar, but if you look it up for epilepsy, it may be that lower doses are common & therefore could cause a change.
sounds like displaced aggression to me. Even my cats do this - they get upset about something, then go swat a different cat that had nothing to do with what happened. It's common.
Make sure you make a heartfelt apology to your friend.
you never know - my brother got severe tourette's syndrome from psychiatric medication, so now he yips and barks like a dog and is frequently jerking and I think he is having mini seizures too, been going on for more than 10 years now. It was either the lithium, prozac or the combo that did this to him. a psychiatrist would say no, those drugs don't cause that, but there are many unknown risks to medications.
You ought to keep a mood chart - psycheducation.org has one you can get for free.
Also, it wouldn't hurt to see the other side of this overmedication problem that's going on right now - read anatomy of an epidemic by robert whitaker, and have your parents read it too. it turns out that in the long run, the psychiatric drugs may be harming much more than they help. (in the long run). I took 25 different meds alone & in combos and even had ECT and all were failures or made me worse. I was told I was a rare patient, and so was my brother, but it looks like that may not be the case - we just had more alert relatives than many others, I think.