oh. my. fucking. god. are you serious OP? how old are you?
i dont want to sound like an asshole, but goddamn people are getting more and more stupid these days. must be all the concussions.....(i know, poor joke).
seriously, your aunt, a brain doctor, is telling you to sit out after you have had not 1, but 2 concussions in less than a week....are you're coming on HERE and asking if you should listen to her? my hell.
im not an MD, but i do have 8 years worth of biology education (im 2 years deep into my PhD in cell biology) and i've been around the medical field my whole life (mother is an RN). i've also had 3 concussions in my life time. do NOT screw around with these injuries. hell, your brain is probably still swollen and not functioning properly. it can take months or even years for some concussion sufferers to return to completely normal function, and you've had 2 in less than a week.
helmet or no helmet, if you have even one concussion you should take a long break. you need time to allow your brain to recover. even if you did not damage your brain during the concussion, there is still swelling that will affect its function. this swelling can put a lot of pressure on the brain and if you were to hit your head again you could do more severe, even permanent damage.