We will have to rule out causes of syncope
from cardiac and non cardiac for which you will require detailed history, thoroughly clinical examination for heart like ECG,blood pressure measurements in different positions like supine,sitting and immediately after standing.
The underlying cause could be vasovagal, orthostatic hypotension
or postural tachycardia
,neurogenic syncope or syncope due to anxiety
etc.Blood in stool
could be indicative of bleeding from distal/terminal portion of GIT I.e. from large intestine to anus.So,it must be evaluated further if it remains constant otherwise it could be temporary and generally subsides by itself.
You will have to consult your physician first for thoroughly clinical assessment to detect the underlying cause.
Treatment will depend on the underlying cause.
Meanwhile you can do this things,
1) Maintain proper hydration and electrolyte balance by taking proper fluid intake throughout the day.(considering that your heart and kidney functions are normal)
2) Positioning on the grounds immediately whenever there is fainting spells
and leg elevation, will cause pooling of blood in the upper part of body mainly in brain.
3) Always wait for 4 to 5 minutes before standing or getting up from the bed means never change the posture so suddenly.
For,menstrual regularization,you can take mensovit plus
otherwise consult gynecologist for further advice.