Sorry about your multiple losses. As an addictions specialist I can help give you some of the information you need to facilitate motivation for change. Ultimately it is up to you. I suppose you have been contemplating a desire to stop drinking or you would not have posted this thread. You may prefer private messages, but a few general facts you may or may not know:
1. If you experience withdrawal symptoms you may need to use a medical facility for detox. Alcohol and Benzodiazepine are the only substance in which withdrawal can be fatal.
2. Alcohol, like many other drugs, impacts one's ability to produce serotonin, which is one of the primary neurotransmitters that regulates mood. In the short-term alcohol use will make you feel better due to dopaminergic effects, but ultimately it will cause emotional instability and increased depression.
3. In the same vein; I won't bore you with neurobiology, but for many of the same reasons the parts of your brain that process motivation are impaired. Find ways to produce oxytocin (a hormone associated with pair bonding), not dopamine. You'll find it does much more for your general happiness and sense of belonging. Social interest is an important key in human development and evolution.
4. Drug and alcohol use do not change reality. You still have issues to work through, including substantial grief. When you sober up those issues are still there, and possibly new ones (like failing grades, loss of employment, etc) that will exacerbate the situation. If you feel overwhelmed like you cannot manage all of this on your own get professional help; it takes a stronger person to ask for help.
5. Everyone has something they are addicted to in one way or another which causes impairment in their life. These days there are many resources to help people who are struggling. People may judge, but as the Bible says, 'Let he who is without sin cast the first stone.' Support groups are a great way to see you're not alone. We all suffer and we naturally gravitate toward the quickest and easiest way to alleviate pain; even if only temporarily.