Thanks for the quick responses. I just opened a test bottle and there was a very loud "pop" sound from it. Loads of head too when I poured it.
I'm really just concerned if the bottles are going to blow up at any point.
If you just bottled this on Friday, why are you opening, i.e. "Wasting" beer now? They're not going to be ready for a minimum of 3 weeks. Every one you open early is one less beer you're going to have
when the beer's are actually drinkable.
You're not in danger of bottle bombs. Your beer is going to be slightly over carbed for it's style, but so what. If you look at carbing to style charts, you'll see that carbonation for each style is usually a range. Some folks, especially Americans who grew up drinking highly carbed "fizzy yellow beer" are actually conditioned in many ways to prefer the high end of the carb range. The 4.5-5 ounces of sugar is meant to produced 2-2.5 volumes of c02 in a 5 gallon batch of beer. What you added is tantamount to ONLY a quarter ounce extra of sugar/gallon of beer, so where you would have normally had 2.5 volumes with the whole 5 ounces, you probably have around 2.8 or so....nothing to worry about. Your bottles aren't going to explode (they're rated much higher than that, more like 3.5 volumes.)
Right now opening them you might have popping and or gushing not because there's a problem,
but because the co2 is in the headspace, not in SOLUTION yet. So it's not really a judgement of if your beer is over carbed or not.
Just walk away from them for a couple more weeks. The yeast don't need you to hover over the bottles. Just let them do their job. You've done what every new brewer has done at one time or another, had more trub loss or racking loss that you accounted for in priming sugar...so what? It's not the end of the world, and it's not like you added an extra OUNCE PER GALLON of beer or something, when you think about it in terms of ounces per gallon, it really isn't a heck of a lot of extra sugar....