Need input-out almost 3 months-having some problems.

I am so thankful for this board. I am out three months almost from surgery. I have had a few issues. First, I have severely cracked mouth sores at the corners of my mouth. They are not cold sores but cracks that open up. I have read on the net and it seems to be caused by vitamin deficiency. I take all my vitamins. This started after surgery and it heals up and then comes right back again, since surgery. I have used different things on my lips but it keeps coming back. Anyone heard of this? I read B2 or iron can cause but I take all my daily vitamins religiously. 

Second issue, sometimes when I eat I get a mild form of dumping. It isn't from eating sweets, I think its from eating too fast, too much or maybe drinking with food. I am guessing that makes the food go thru into the intestine too fast and I have really worked on it. I have found that eating solid protein, meat/chicken/fish makes me feel the best and carbs can cause this dumping thing. My symptoms are headache, nausea, hot flashes, and I have to lay down to sleep it off. I haven't had diarrhea though. 

I am hoping this second issue is resolving itself as I am learning what foods are best and how to slow down, etc. Also, I have been pretty tired the last few months and I take a nap everyday. 

The mouth problems are really painful and worrisome. It makes me have doubt about having the bypass, worrying that my body will not be able to get the nutrients it needs. Any thoughts will be welcome! Thanks, Tracy