Is it worth resitting my gcses?

I achieved 99887776 and D2* in my gcses. Two 9s in English, 8 in biology an 8 in maths , a 7 in chemistry physics and computer science and a 6 in music. I got a D2* in ICT. I'm currently doing fm, maths and biochem for a levels. I'm looking at applying to a Russel group university but I'm worried my gcses will hold me back. I'm looking at applying or UCL or Cambridge ( though that seems highly unlikely now ). I was really shocked at my gcse results and felt like I could have done better. I'm looking at applying for medicine but once again after my gcse results this seems unlikely. Would it be worth resitting chemistry and physics gcse and maybe even biology? And then possibly taking on a humanities gcse as I'm naturally good at humanities ( I would have to teach myself). I'm not sure