Vascular dementia symptoms and conditions

I started taking Singulair 6 months ago. My allergies even with medication and immunotherapy were becoming unmanageable. My larynx would swell up and close my throat and make breathing difficult. I had trouble breathing at night laying down to sleep, my voice was hoarse most of the time. Within 2 days after starting Singulair, those symptoms totally disappeared. I thought it was the answer I had been looking for. I've had a lot real problems in the past few months with crying and sadness, but with my Mom in hospice with Alzheimer for 14 years, and my father breaking both hips last year, my mother-in-law with vascular dementia, and an insulin defendant diabetic, and losing my job due to outsourcing, and other stressors in my life, but II thought my sadness was all of this stress. Counseling wasn't really helping and I've got a new counselor now. In the past couple of months, my mental state has become more and more fragile; I have times that I wish I could go to sleep and wake up in a couple of months or just go somewhere and be left alone. I am angered easily; I have always been happy and easy-going. I cry daily and don't get out much, and I'm afraid of the unknown now. I feel like my self-esteem is in the toilet.

Tonight I have stopped the Singulair. I'm afraid because I know the allergy problems will return, but I'm hoping that I'll be able to manage them somehow. I have 'a lot on my plate' right now, but at least if I stop the Singulair and I feel better mentally I'll know it was the drug and not my life.

My Mother was diagnosed with Rheumatoid arthritis 30 years ago. She has been on prednisone at low doses since then. About 3 years ago she started imagining things, and hallusinations. About 2 years ago her prednisone dose went up to 60mg a day due to a stroke of the optic eye nerve. She has since been tapering down, now at 15mg a day. But tapering down makes her arthritis more painful. She has developed diabetes, loss of sleep, loss of apetite, loss of muscle tone. When she gets bumped, it's a big opened gash, rather than just a bruise. With the higher dose she was more moody & would get angry easier. The hallucinations & paranoia continue & are making me more & more concerned. I haven't read about this in any of the stories. Has anyone else experienced this side effect? I spoke with her Rheumatologist who suggest a psychiatrist to prescribe anti-psychotic drugs. She's already on 11 pills a day, does she need another?
Please let me know if anyone has experienced this as well.
Thank you.