Side effects from Dilantin, treated by upping it???

Hi, New here. 53 just diagnosed about 7 months ago after massive grand mal that put me in ICU for 3 days and discovery of large Mes. temporal. Lob. Sc. and I learned that all those things that all my life just made me a "weird kid/adult" were in fact seizures. Anyway, after having some allergy problems with some seizure drugs, i am currently on 600 torkendi (sp?) which is basicly 24 hr topamax. And the docs added Dilantin 300 to it. Within a week of adding the Dilantin I started feeling depressed and crying. I had several episodes of total breakdown, which is not like me, and though I didn't feel like killing myself, I had no will to live. Upon calling my Neurologist about it he sent me for blood work. It showed my Dilantin levels were very low. 2 out of a range of 10-20. So he raised my Dilantin to 400 with follow up blood work in 7 days. When I told the nurse I was concerned that I would feel worse,(I never got to talk to the doc that day) she said she would check and call me back. She called back and said that the dr said he felt that I had just enough Dilantin to upset me but not make me better, that sometimes meds like this can make you feel terrible if you don't have enough. And assured me I would be OK if I upped it. As you can imagine, I'm a bit nervous. Anyone ever hear of this before? Anyone have experience with this? I'll up it if I'll feel better. But I don't want to get more depressed Thanks Kris