Hi coralinna,
The expression itself sounds fine to me, but the verb tense seems wrong in the context. As everything else is in the past, I would change the phrase in bold to "my life completely changed course." As it stands, the phrase in bold is describing what is happening in the present, and you would need to revise the sentence as follows:
Although [no comma] we weren't expecting this pregnancy, we are happy. However, my life has completely changed course. I've stopped studying and I've started to look for a job.
