MsM - sorry to hear about your mom, look what happened to yo and here im complaining about some little problems.
That's all just perspective and experiences. When I was younger, my life was very similar to yours in that what seemed insurmountable to me was rather mundane to someone else's experiences. Don't assume that your experiences right now are minor. The point was more that you can get out of this.

Suicide might be an indication of mental illness but keep in mind that's a generic term that can range from depression (which is what it sounds like) to full-blown pyschosis. Talking with a professional would be worthwhile.

WHat you think of suicide religiously, is it a sin ? or is it not a sin ?
Before answering that, one has to ask if one believes in God and the "Word of God" (or gods or however an individual defines it). AFAIK, only the Catholic faith deems suicide as a sin. Does that make suicide a sin? I dunno. I see some benefit to the idea of assisted-suicide. I've seen Alzheimer's. Not something I want to go through.

Personally, it's a cop-out at dealing with issues. We don't want to face what's painful and ugly in our lives so we look for what is the easy way out. Thoughts like "The world would be far better without me" tend to cloud our own judgement from seeing how much of a difference we do make, minor or major.