3 weeks staying in home (Corona)

Short introduction
I'm 21 years old and I have never been in a relationship. The reason is I'm introverted and have social anxiety. Every time when I want to start a conversation with someone I have same fear, stress, blankness in mind as when I stand on ledge really high having acrophobia(fear of heights).

My goal
My brother is going to marry in half a year and I want to find a plus one. I have no woman friend to even ask. I decided to start meeting new people or even start dating but the problem is whenever I start thinking of meeting someone new my anxiety kicks in.

Free time
My university got closed, because of coronavirus. They told us to stay at home as much as possible. Right now I have a lot of free time that I don't want to waste. It could easily triggers some urges, so I have to fill somehow my day.

Right now I'm looking for a way to reduce my anxiety and to improve my social skills without doing social activities. It's sound impossible because every information that I could find says that I should start talking to strangers, find a group with similar passion or other social interactions. How can I do this if I need to stay at home to not spread the virus.