It can be hard to know if you have head lice. Since you can't see your own scalp very easily, a head lice condition is hard to self-diagnose. The best thing to do is have someone check your head for you.
After looking at lice pictures or lice videos to know what they're looking for, have the person carefully lift sections of your hair and look along it near the scalp. That's where head lice are commonly found, as well as behind the ears, near the neckline and at the base of the head.
Look for anything crawling through the hair. These would most likely be adult lice. Adults are about the size of a sesame seed and will be the easiest to spot. If you see a grayish-white or tan bug crawling through the hair, look closely at it. You should be able to see human blood inside it.
Look at the hair strands within about a quarter inch (~0.5 cm) of the scalp. See if you can find lice eggs (called nits) attached to individual hairs. If you see any, try pulling them off with your fingers. Nits are extremely small and will be glued pretty securely to the hair. So if you can't pull them off easily, they are probably eggs and not dandruff.
If you feel like something is crawling through your hair, those might be lice as well. And if your scalp gets red and itchy, you may be allergic to lice bites.
There may be a professional lice-removal business close by. If so, check with them to see if they will do a lice check for you. They deal with lice every day, so they will be able to let you know if you have head lice.