The word 'theory' when used in the scientific sense means:
A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world. Wiki
So, you'd have to apply your same doubt to the following:
- Germ Theory
- The Theory of Gravity
- The Theory of Relativity
All evidence - fossil records, genetics, geologic, biology, biomechanics, geographic isolation - confirms evolution. I'd encourage you to check it out. Life, and how it changes over time, is amazing.
Amen, I used to hold a skeptical view of evolutionary theory until I went out into the field and confirmed it by my own observation... then after studying more much of it became fact to me.
Also all of the relevant sciences continue to confirm each others findings.
There is a thing called the law of witnesses; and evolution continues to comply, with the case growing stronger every decade.
There is a caution though and that is not to adopt evolution as a religion as some have done, because that just reverses the problem.