Nothing special in my experience. You can get it pretty easily online, just start low to make sure you don't expose yourself to any complication blood pressure wise. Guanfacine is a lot smoother than Clonidine, so its worth a shot - I just wouldn't expect much out of Guanfacine.
To be fair strong anxiety is one of the hardest things to treat in my experience both long term and short term. You are better off using an app like buddhify 2 and practice meditating and dealing with it somewhat. I do have pretty bad social anxiety, I think due to being on the autism spectrum + prior brain damage, but prefer a balanced method of drugs, nootropics and meditation (psychological based methods), unfortunately its not perfect and sometimes the anxiety does get the better of me, but it does allow me to live a far normal life than I could otherwise.
All drugs that works effectively on anxiety seem to wreck havok on cognitive functions in the long term - such as benzos, opiates, SSRIs , GHB, lots of alchohol ( a common self medication method), in the end all effective drugs on anxiety (the ones I know anyways are common depressants) change your behaviour slowly over long periods of time, they make you lose your memory, creativity and so on. Horrible anxiety require powerful drugs to alleviate completely. I prefer benzos because it allows me to selectively lower my anxiety when necessary, and allows me to balance drug use with other psychological methods, but it has addictive qualities that can be dangerous.
And also trust me, irritability and anxiety is torture, but its a blessing compared to depression. You don't want depression, its way worse. Can you imagine being devoid of meaning, purpose and emotions? If I had to choose I would pick anxiety over depression everytime.
Oh and if you have trouble sleeping I recommend trying 10 to 20mg of Melatonin + 1000mg of Valerian Root 2-3 times every week.
General over stimulation can be caused by a variety of different things, I guess you should try to figure out the underlying cause if you haven't figured it out already.