OP,
I am truly sorry to hear about your loss. Losing a loved one due to a long illness, its hard to watch them suffer, but in a way, you get to build yourself up for the impending loss. Suicide leaves an immediate hole. You ask yourself the obvious questions, but never realize the obvious answers. Just know that she loved you, and your final conversation, there wasn't anything that your mother probably would have wanted differently. It may hurt now, but eventually, you'll be thankful for that last conversation.
I lost an uncle and a grandfather to suicide. The best advice I can give is:
Don't hold anything in. You need to talk to someone, whether you realize it, or not. Suicide can leave a lot of emptiness. Whether its a close friend, or a counselor, you'll need someone to let your feelings out to. Hell, even write them down in a journal. Anything.
My dad refused to talk to anyone for a long time after it happened (it was his uncle and father). I could see a difference in my dad, and it was tearing me apart. I finally sat him down one day and told him what I was seeing. He went and spoke with a pastor, and while he ended up relying on faith to get him through the pain, he was finally able to find an outlet for his grief.
Just hang in there, OP. If you even want to vent it to me, feel free to PM. Just know that your days will get better, she'll always be in your memories, and as long as those are there, she'll always be around.