Feeling wretched

I don’t like moaning but I feel like I’ve gone from being able and strong after recently being diagnosed with a metastasis from the lung, The lung cancer was diagnosed 3 years ago, tNow I’m an absolute physical wreck since starting Osimertinib approximately 6 weeks ago. I’ve had non stop diarrhoea since week 3. My dosage of Osimertinib has been halved but still feeling no better. I’m weak, tired and finding everything such an effort. I’ve just had my first monthly injection of Denosumab to protect my bones as I have osteoporosis and the Osi can weaken them. This can also cause diarrhoea. I don’t know what to do and my mental health is suffering. I’ve always thought of myself as a glass half full person but I’m feeling suicidal. My husband is an absolute arse who gives me grief and I’m divorcing him. Just want my freedom. Has anyone else had severe symptoms on Osimertinib? I feel like telling my oncologist I’ve had enough. My daughter thinks I should stop the treatment and try a course of chemotherapy instead. Any advice is much appreciated. Sorry for moaning.