I’ve just registered for 3 courses for the winter. All of them are online so at least that will save some time. Wish me luck guys! 
A typical semester is 16 weeks long, and 16/2.5=6.4 6.4*18 credits=115.2 credits for an entire semester if you kept up that pace. Essentially, taking 18 credits in 2.5 weeks is the equivalent of graduating college in 1 semester. Don’t do it.