I just wanted to share a bit of my own experience so far and how you might want to approach courseload and social life in your first few years of college. It may seem tough at times, but you can turnaround your situation as long as you never give up!
So, to start my HS career was a tale of two halves, I did absolutely nothing my first two years outside of classes. My GPA was middling and I had 0 social life (struggling with depression for a long time).
After a few life changes, I kicked myself into gear and decided to take several AP courses in History and English as well as some college level courses in Math and Speech. I also decided to get involved in several clubs like Science Bowl and Yearbook. I found that all of this increase in workload still left my like 0 time for a social life. However my GPA was able to turn around completely and I finished with a 3.97 my last two years and combined with a soild ACT, I was offered a near full ride to my local unit which am turned down to go to community college for free (advisors, parents were not happy about that decision).
Didn’t take a very large courseload on since I was ahead of the game my first year. Finished 27 credits and kept a 4.0 while getting involved with one clubs, I was also able to regain a social life for the first time in a half decade.
This year though has really shown me my full potential though, I made the decision to grab 3 associates degrees while I am here and took 19 hours accordingly (including accounting, Bio, Honors Literature). I also became not only involved with, but quickly president of 4 clubs including SGA. My social life is flourishing, seems like I am always doing something. I am also working pt about 15-20 hours a week. Still maintains my 4.0 it seems as well!
The gamble that I took turning down the uni scholarship seems ready to pay off, I look to be on track to land one of the few full rides they give to transfers through their honors college. I am also in the running for All USA CC Academic Team which I am very proud of.
Advice tips:
Get involved with as much as you can, but ease into it so you know your limits
Courseload is about scouting and ambition (12 is too much for some, 20 is too little for others)
Don’t let one bad experience crush your entire life
Advisors are an asset, but you know yourself better than they do
Be sure your schedule represents you as a person (I have all of mine b2b, others need a break in between)
Make connections
Don’t fall into the “I need to narrow my interests trap” (not to say that you won’t eventually have to pick one major)
Clubs can be a great source for friendships, job info, and travel prospects.
Know that you may not be the best, but that your worry puts you at an advantage over many others
College is supposed to be the best time of your life, have fun! (Mostly responsibly) 
I just wanted to post this because I know a lot of people feel defeated at times during HS or because they have to go to a CC, but remember that the opportunities are always there. I battled a volatile family situation, dealing with being gay in the south, depression and anxiety at times, injuries, accidents and trust me I was at my wits end a couple of times but I just bent a little bit more instead of breaking and it seems to be paying off big time.
Hope I can inspire someone with this or at least give you a feel good story for the day.