how do you maintain going to the gym with social anxiety

i'm a male in my 40s, i have to go to the gym to maintain my health, because i acquired type 2 diabetes years back.....but ive had a hard past and suffer shyness, low self confidence, low self esteem and have social anxiety...publically i'm usually very nervous, shy and come off as socially awkward...i pay 53 pounds every month to go to a private gym, which is just across the road from me....but it is a big ordeal to go there, i don't like being around younger lads but don't mind being around other men and elderly men....i see younger lads as a threat and they unnerve me.

how can i keep on going to the gym when i have these problems? i only go to the gym to swim in the pool, and i'm very nervous during the whole stay at the gym, i get scared someone might start trouble with me, as i've been bullied and harassed in my past.