Prenatal vitamins

Ok, so this is my first month TTC.. I've recently became obsessed with it and have done a lot of research. My fertile window  ended today and of course I already getting antsy! And every little feeling makes me think that I may actually be pregnant. Probably a newbies wish right!? 
Anyways- question is .. I read/heard its good to begin prenatal vitamins before getting pregnant- one thing I have read is that it can give you side effects of bloating and constipation AND boy do I have that! I am using Nature made ... Is there a better one that I could take ?! Should this feeling subside?  And could some of the symptoms I'm feeling be another side effect from the vitamins? (Indigestion,sore breast, cramping, head aches dizziness) I realize that me wanting to conceive could be a big reason why I'm feeling these things as well!?