What you have described is a common problem and is a natural reaction. When the sun is shining the brightness and glare interfere with comfortable vision and the ability to see clearly by causing squinting and eye watering. This is caused by the UV rays in the sunlight. This is why people are advised to wear sunglasses to protect their eyes in the bright sun. When choosing sunglasses make sure you pick a good brand as your eyes can be affected by substandard lens that many cheaper sunglasses use.
Many medications make you sensitive to sunlight so check your medications. Also, most light eyed people are sensitive to sunlight. It's called photophobia. Basicially it means you have light sensitivity or intolerance to light. I have green eyes and have always have this problem and what makes matters worse is I hate wearing sunglasses, or anything on my eyes. Since you have photophobia I would try to wear sunglasses whenever you're out.