Conception prenatal vitamin

So I started taking it a week ago and I'm noticing more fatigue after I take it, less appetite, difficulty going to the bathroom, and my urine is like neon yellow. Is this normal? Also, I'm anemic and b12 deficient, and have chronic migraines that I'm noticing that they're coming back, and I'm having vivid nightmares again. Granted I've had issues with all this before just not in a while and not while on a prenatal. Is it just coincidence that it happened around when I started taking this pill? I'm only 23 and my husband and I are trying to conceive our first child. Any advice would be so greatly appreciated.