Spotty connections

My connections to some networks are spotty! I cannot post, make comments, like, etc. on Substack and  

I have lost some connections with Youtube!  Everything was fine yesterday morning but I'm having  problems with the internet today and yesterday afternoon!  Could it be the outside lines due to recent storms? Or something else?  Do I need new equipment or a new computer? Do I have to call Xfinity? Thanks.