Welcome to the group and thank you for sharing your experience with us . .. I am not a med professional so what I am saying is from personal experience . . .it may or may not help . . .
For me, it is not unusual to mirror the symptoms that we fear the most . . . even though your dad has recovered from his heart attack, you probably are very familiar with the symptoms. Coupled with being anxious about your dad's health and maybe projecting somewhat on to your health, then it is quite possible that your physical symptoms are triggered by your anxiety which, in turn, triggers the physical symptoms . . . for some of us with anxiety, alcohol, especially in quantities when it produces a hangover is a dangerous combination . . . alcohol allows anxiety to run free in the mind and, also, the hangover simply intensifies physical reactions . . . it is also not unusual that anxiety manifests itself in dizziness and vision problems . . . for some, it is because of the amount of adrenaline produced with anxiety and for others it is an instinctive reaction to lower blood pressure in preparation for fight or flight . . .given that the opticians have given you a clean bill of health from the vision perspective, then these physical symptoms could be related to anxiety . . . as for hearing or interpreting people's statements as strange, well, anxiety can make us distracted and distant and this can make it difficult to process information appropriately . . .
Now, having said all of that . . .our brains usually do not stop forming until our mid-20s so now is a good time to deal with anxiety . . . I know that socializing and drinking when you are 20 go hand in hand but they need not do so . . . do you have to be drinking / drunk to have a good time? it's something of a decision making process --- you have a choice . . . drink and pay the price afterwards or take the time now to resolve issues of anxiety and see your friends in non-alcoholic situations . . . if you all need to be drunk to have fun, and, again, yeah, I know this is the culture, then you will have to make the best decision for yourself . . . .and right now, drinking does not seem to be doing you much good . . .
I honestly do not think that you are losing your mind . . .despite saying you don't worry about anything, I think you might have some residual worries re: dad . . . . you do not have to take meds . . . for some, meds are a lifelong commitment and for others they are a bridge and still for others meds are not used . . .that is a personal decision . . .what I would suggest that you consider is getting some directed counseling to help you identify the triggers to your anxiety and manage them so that you can get past this road block now . . . but, really, what you have described is for me quite typical of some type of anxiety and it does not need to be a long term disorder . . . if you work with a counselor, find one that has experience in the area, who is there to help guide you to develop strategies, and who listens to you . . .this needs not be a psychiatrist who often deal more with symptoms than root causes . . . you may have to "interview" several counselors to find one with whom you are comfortable but that's okay . . . the counselor needs to meet your goals and not the other way around . . .and remember, this is a process not a one time event . . . you do need to engage but at your age, now is an excellent time to deal with your anxiety now . . . but I doubt that you are weird or losing your mind . . . do let us know how things are working out for you and come back here any time . . .even if just to say hello . . . .and if you need any support, know that we will do our best to help you . . .take care, kc