#1 you are not alone, more than half the world has your EXACT same problems and if they say they don;t than they are lying. I work in healthcare, i see it every day, and anxiety manifests itself in many different ways. It just feels wrong because it's considered taboo to talk about it or admit you have a problem. So being that you feel in such despair I think it is REALLY important you talk to a mental health professional right away. You want to stop this before your thoughts get the best of you and you spiral down in to a worse depression or start exhibiting agoraphobic tendencies which are hard to break. That's just my experience.
With me, when i get anxiety, i tend to get weird health problems, nausea, diarrhea, swollen lymph nodes, aches and pains, fatigue, headaches, i even get ocular migraines. I have fear of the unknown, and i think of What if scenarios such as what if i have a panic attack in public. What will everyone think, will they laugh at me, or just pass judgement and deem me crazy? The funny thing is that all this goes on in my head, but no one thinks anything is wrong, so i am really good at hiding it and pretending too be strong when inside i am dying. I am on my 12th day of zoloft 50 mg and these feelings are starting to go away, i still have them, but i can rationally think them out and stay more calm. I do have to say the first 2 weeks (but are getting better now) caused major increased anxiety and nausea really bad (i lost like 15 lbs) but it is working because i am getting my appetite back and feeling more calm. The only problem i have now is when i first wake up in the morning with a speeding pulse, but i know that will stop too. (this is my second time on zoloft).
Some things that help me, is breathing. When you feel an attack, inhale deeply through your nose. Imagine your lungs fully filling up with air. Hold it 5 seconds, then exhale through your mouth. Repeat for 5 or 10 minutes. Also, keep a worry journal. Write down your fears throughout the day and designate a 20 minute time period where you can sit down and reflect upon your fears. Each time you get a worry, just write it down, and say i am allowed to worry and have run-on thoughts but not until my designated time period. Also, it's important, even though you don't feel like it, to keep going out and remain active so you can prove to yourself you will be fine in public. Also, no caffeine, that speeds up your heart rate and can cause a panic attack. Hope this helps!