I'm so sorry. You are overwhelmed with fear and we all get it.
Ok, first: breathe. When you start to panic, do a 4-7-8 breath. Seriously, it will help. Exhale completely then softly close your lips and inhale through your nose to a count of 4. Hold it for a count of 7. Now exhale through your mouth to a count of 8. Exhaling for twice the inhale time is really important so don't cheat. That's the part that calms you. Do it at least 3 times. It's a natural tranquilizer.
Second: stay away from Dr. Google. You'll find as much bad information as good information and, truly, you don't have enough data at this point to get any relevant information even on the reputable websites. You'll only make yourself crazy. Don't get ahead of the data.
Third: Your mind has gone to worst case, and that's natural. We've all done it. Even if it's metastasized, it's not an automatic death sentence. I won't lie to you, it might be a life sentence but your life might last a whole lot longer than you think. Those statistics? Ignore them. All those statistics tell you is that X number of people died within X (usually 5) years from diagnosis. It doesn't tell you anything how they died (car accident, etc.), only that they died. They didn't necessary die of cancer or anything to do with cancer. I'm a Stage IV patient with colorectal cancer that metastasized to my lungs. I was diagnosed 3-1/2 years ago. There are other people here, also Stage IV, who survived at least 10 years and are still around -- some have even been cured. The state of cancer treatment is evolving very quickly. The next big thing might be right around the corner.
Instead of Googling all the horrible things that could happen, start looking into your nearest cancer treatment center or hospital and find out what complementary services are available. Where I get treatment, they offer all kinds of classes - several forms of yoga, tai chi, meditation, arts, music therapy, etc. - free to cancer patients. They have a gym with personal trainers, also free, plus social workers and dietitians. Make friends with the social worker. He/she will be able to help find you services when you need them - maybe a ride to/from treatment, or someone to walk your dogs, or a service that will check on you, etc. The mind-body-spirit connection is real and it's powerful. Whether you are Stage I or Stage IV, give your body a good fighting chance. Also, you mentioned that you're introverted, but start reaching out to friends, neighbors, and family. You might have to step outside of your comfort zone but try. Please. You might be surprised at the people who jump to help, as well as the people who can't deal with it. As to the latter, don't take it personally. Some people just don't know how to cope with so much as the mention of cancer.
Be sure to come back after you know more and let us know what's going on. This is a terrific community and we're here for you. Let us be your friend.
I hope this helps.
Nov-2009 Early stage CRC found during routine colonoscopy
2010, 2011, 2014 F/U colonoscopies, all clear
Jun-2016 CRC during followup colonoscopy, surgery, Stage 4, KRAS, MSS, inoperable lung mets
Aug-2016-May-2018 Folfox, 5FU & Avastin, 5FU, Folfiri & Cyramza
Aug/Sep-2018 YAG laser surgeries (Germany), 11 nodules removed
Nov-2018 clean CT scan
Mar-2019 New lung nodules
Apr-2019 Dec-2020 Xeloda/Avastin, SBRT, cont. Xeloda/Avastin
Dec-2020 Progression, considering all options