Hi.
Your feelings are completely normal. Guilt and regret are some of the most common feelings that surface after the death of a close family member. We often look back wondering what we could have done differently and what we could have done to show that person they were truly loved.
It seems to me that before your mother died you were just being a teenager, doing what teenagers do--living a normal life, enjoying your friends. If your mother had been sick for a while, chances are she actually wanted you to live your life and not be too burdened by her illness. So try not to feel too guilty.
If your mother's death was sudden, I'm sure it must have felt like a violent separation--a shocking one that makes the lost opportunities more apparent. These feelings will eventually fade, however.
It's really hard to get over the loss of a parent, but time will heal. Just be patient with yourself and don't be afraid to ask for help. Talk to friends and other family members and seek professional help, if you feel it's necessary. Your school counselor should be able to offer short-term counseling or refer you to another mental health provider for more extended therapy.
All the best,
