Anxiety increase Zoloft side effects?

Just started Zoloft for anxiety/depression-started at 25 mg and then after two weeks increased to about 40 mg by cutting pill in half. Third day at that dose noticing increase in anxiety, shakiness, restless, headache. Assuming these are all side effects and will pass eventually. I need some reassurance that this is worth it. I have so many other medical issues (cancer treatment, migraines etc.) which are causing the need for the Zoloft I just feel hopeless that I will ever feel good physically or mentally again. I am getting some counseling from the oncologist office. Thank you!