I think that I have had SA my whole life, but I managed to finish school and get a degree! Then things went totally downhill for me. I've always struggled with blushing and sweating in situations that made me uncomfortable, but it has got to the point where I can't leave the house without breaking into a sweat. This makes me just want to stay home too, and even having people come visit me at home puts me in a total panic.
Anyway, I just wanted to agree with everyone here that you should try to get professional help. Back when my SA was increasing but wasn't totally unbearable, my mom suggested that I see someone. I was very reluctant but agreed to go. Going to the appointment was a major ordeal, but professionals are used to dealing with people like us, and will not judge you. The appointment also gave me hope as I was put on medication to help me cope with my anxiety. Although the medication seriously disagreed with me, I was also told to go for cognitive behavioural therapy.
Obviously going to the therapy sessions was and still is quite anxiety-provoking, and if you are a shy person like me you may feel that you won't be able to open up to your therapist. Eventually I was able to speak freely about the extent of my problems. I still feel depressed a lot and sometimes doubt that I will be able to overcome SA, but I really find that seeing my therapist once a week helps me to deal, gives me new hope and will eventually help me to live a normal life again. Without him I would be totally depressed for sure. It is so important to have this kind of support, otherwise I think it is almost impossible to overcome SA.
Apparently only a quarter of SA sufferers seek help, which is really sad.
I'm sure, like others said, that you can get a therapist to come to you. Especially if they specialise in cognitive behavioural therapy, they will understand your situation.
Good luck, I hope that you get the help that you need.