I too faced considerable uncertainty with regards to my major. I ended up changing majors two years in a row, effectively wasting that time and money. It is hell. Avoid this.
How to avoid this? Do research. The more you know about the major and careers which it leads to, the better you'll know whether you like it or not. Do a google search on 'a day in the life of a *', read wiki and textbooks about the subject, watch youtube videos, hell maybe even ask a professor or someone working in the field if you can muster up the courage.
And once you do pick something, fucking stick to it. Don't be wishy washy, you've fucking picked it now so devote yourself to it. If you're having second thoughts you probably don't like it that much/still don't know enough about what its like.
Yeah it is.