Feeling terrible because of fear of purgatory

To keep this brief, I'm deathly afraid of purgatory. Whilst I do know that purgatory is definitely better than hell, I'm just deathly afraid of going.

I feel so terrible, I feel down. Today was supposed to be a good day because I went to watch a movie with my family, one that I was so excited to watch. But this fear hit me like a truck.

I can't stop crying, I can't think of anything else. I just read the 'Treatise on Purgatory' by St Catherine of Genoa, which was supposed to make me feel better, but now I feel worse. I get that we feel intense happiness, but also intense pain. I don't want to suffer pain, I don't want to burn, but I don't want to be unworthy of heaven. (Which I definitely am)

I just found out about indulgences but it's not like I can always do it, even if partial because I'm a minor (15), and can't go to a church, etc, anytime I want. It's so bad that it's affecting those around me, my dad is blaming me for feeling this way and my mom got irritated because of me feeling down earlier.

Also, it's like every venial sin you commit gets added to the time spent in purgatory, and the average person probably commits venial sin everyday. I can never catch a break.

Someone please help. At this point I rather be martyred than have to suffer after death.