Ok I'm going to sound like one of those water purification experts that posts on RC but I'm really not
A typical setup (and by typical I mean usually what they give you with your system when you buy it) is you'll get a 5-micron sediment filter and 2 5-micron carbon filters (carbon block filters are best though as you don't have to worry about "carbon fines" clogging up some filter down the road). Now you'd think no problem the sediment filter is 5 microns so that should snatch up anything that could potentially clog up the carbon filter. Not quite the 5 micron filter actually can let some things in under certain circumstances as big as 10micron! As they don't go around and check all the holes to make sure they're exactly 5 micron
What I've gone to is a 4 stage prefilter, where I have a 5 micron then a 1 micron sediment filter, then my 2 carbon filters. However depending how fast it goes through you might get away with a single carbon filter, there's a particular contact time water needs with the carbon to strip out the chloramines can't recall what that is off the top of my head however, but sometimes have two carbons is nice just for the added protection.
Before you order new filters, I would first find what the problem is, take out one filter, then turn the water back on, put it back in then take out another filter, etc until you find which one is clogging your system. However the fact that your pressure dropped to zero is quite strange, you should get a bit of trickle through there at the least! Unless your water pipes have so much gunk in them.... you might want to go with a 5 micron then 1 micron sediment filter if that's the case.