universities don't really look at gcse's. they look at your a level grades and you only need 5 A*-C gcse grades to get into sixth form, so you should be fine. as long as you have good grades in english and math at gcse and you get top grades at A-level. you should be fine, if a university was likely to be picky about gcse's it would probably only be oxford/cambridge/durham - the really top ones.
i know it sounds a bit confusing but hope this helped!
You need to have at least 5 A*-Cs to be able to do level three courses at sixth form, so if you can get that much at least, you're fine. For universities, they don't really look at our GCSEs, I've been told that they simply pay attention to your predicted A-levels since the your GCSEs are not what are going to really help you or even prevent you from going to university, it's the A-levels that will
I don't think you have anything to really worry about..