You don't have to, i probably wouldn't recommend a bridging course exactly, you would just need to put more effort into studying etc. all of the information you need is in the textbook so when and if the time comes just put the effort into teaching yourself all the terminology etc you're not familiar with.
I cant even remember why i was interested in it, mum wanted me to be an OT, so maybe it was a half way compromise. However, OT as a backup wont really work because im nearly certain that the OT uai is higher than the spth uai, so if you dont get into spth than you wont get into ot.
I can assure youll consider dropping out. the work for this course is really boring (and near impossible to complete some assignments), pracs make it all worth it, but they are few and far between so youve still got to be determined enough to stick with it through the 2x 2000 word essays due each week when semester is nearing its close knowing that exams are looming ever so close. I should stop procrastinating now.