Pregnant 5 wks 4 days , is it ok for me to use my treadmill & is feeling super hungry all the time..

I just found out Im pregnant so my friends and family told me to stop doing exercise for now.. May i know at what month or weeks can i start back using my treadmill.. i've gain alot 4kg eventho it is just new.. I been feeling hungry super hungry my both pregnancy before 19 year ago is not like this.. Is it feeling super hungry normal?