Can my hemoglobin be low and my RDW be high because I just came off my menstrual? All other labs normal

Iron. Yes, in young woman like yourself , menstrual period- especially if you have heavy period- you can have iron deficiency anemia- that can be presented with low hemoglobin and elevated rdw. Having said that other condition beside iron deficiency can also give the same presentation. Go to see your md and get your iron checked at the very least.
No. Look for another cause of your anemia, perhaps iron deficiency. This does not develop overnight from having your period.