What Causes Weakness And Tiredness Before Periods?

hi there,

I feel weak and tired. i have slept almost 5 hours during the day today. my muscles ache. for the past 2 days ive been eating (small portions) every 3-4 hours and for some reason still not satisfied after the meal, my stomach gets upset and then after an hr or two itll be fine. i just started my menstration today, been moody all week. the problem is im just so tired and weak throughout my entire day. i normally dont get this before my menstration