I did those but with further maths, not chemistry. I also had to self teach history!
If you work hard, you should be fine, even with shadowing, and you should be able to keep your social life pretty much as it always has been!
If you really want to do those subjects then it is doable so you can do it, but if you aren't sure about one then don't bother forcing yourself to do it!
You can always start with 5 and drop down to 4 if you want to.