Change in mole on stomach

[HannahCB92]

I've had a mole on my lower stomach for as long as i remember, i'm 29 now. It was a perfectly round dot which was almost black in colour and has never changed until now. I noticed last week that it has changed colour. Instead of it's usual dark brown/black it has now gone a brownish and reddish colour and now it has almost like a halo surrounding it. I have tried to get an appointment with my GP today but had no luck so i will try again tomorrow. I just wanted to know if anyone else has had a similar experience? I don't know whether i am over reacting or if this is all normal.