If you have a strong reactions, it does not mean that you are mentally weak or mentally ill. If you find that after several weeks you are still unable to cope with your feelings, you may want to consider getting extra help through an employee assistance or mental health professional. This does not mean you are mentally ill, but simply means that your reaction needs more attention. The reason is that alcohol works on the way which you preserve memories of recent events. It is very important that your brain have the opportunity to deal with all aspects of a traumatic event so that you will less likely to be bothered by it later in ways that you may not understand.
Caffeine is a stimulant.
You need to relax and be calm. The stimulation of both caffeine and a traumatic event may make it harder to cope and settle down. Communicate about the event. Your mind needs to process what happened so that it can resolve your personal feelings. Talk with your co-workers, manager, EAP counselor, family member and friends.