Sharing your thoughts and opinions is like riding a horse, in some ways. It takes practice and, if you “fall off” (get chewed out for having an opinion that someone doesn’t agree with, and the incident leaves you sore for ages), you have to get back onto it ASAP. The longer you stay afraid of getting back on the horse, the more difficult it will be to start riding again.
If it’s been a long while, it can be difficult. But it’s not impossible.
My first suggestion is to forgive yourself for angering those who didn’t share your past opinions or embrace your passions with the enthusiasm you had once hoped. Then start small. Share headcanons on your favourite shows that are either dead or a small fandom. Work your way up into discussing the material in more active fandoms.
Then, when you feel confident that people are listening (even if they don’t agree), then start sharing your thoughts on real-world issues. Keep in mind that it’s not a good idea to jump into political or religious discussions unless you are confident you can hold your own, and are ready to accept that others will get very testy when they don’t share your views on those particular matters.
Also, another thing to keep in mind is this: If someone can’t discuss the matter with you maturely (ie. without finger-pointing, name-calling, goalpost-shifting or general asshattery), they are not worth the angst. People like that act the way they do because they want to win, not because they want to share ideas. But a discussion isn’t a death match, and you can only win by not playing their immature little games. (There are assholes and trolls everywhere.)
As long as you’re not hurting anyone (ie. spreading hate against those who are suffering or disenfranchised in some way), then your opinion is a valid expression of your core beliefs and personality.
Feel proud of who you are. You have nothing to be ashamed of and nothing to hide. Now repeat after me:
“If they can’t handle it, fuck ‘em!”
As someone who has also struggled with being heard and having the confidence to express myself, I sincerely hope this helps. Because all that really matters in life is having passion and trying to do some good in the world, in whatever small way you can. Don’t let a bunch of naysayers steal that from you. You’re better than that.