I can't tell if I'm having an orgasm or discharging.
Hi there and thanks for your question. If you can't tell if you are discharging or having an orgasm then you are probably not having an orgasm. Instead, you're probably feeling the sensation of being "turned on" and the lubrication that comes with that.
Most people experience orgasm as a very intense pleasurable sensation while others find it less intense, or even sometimes a mild pleasurable feeling. Most people know when they do have an orgasm for the first time because it's a unique feeling—not like something else they would have experienced before.
As you become increasingly sexually aroused, or "turned on", a lot of physical changes happen. Your blood pressure, heart rate and breathing increase. Your skin might become flushed and more sensitive, nipples become erect, breasts increase, pupils dilate and muscle tension increases all over, which sometimes creates a shivering or shaking sensation.
There are also a lot of changes that happen in the genitals as arousal increases. For girls, the vulva (outside bits) swells up, the clitoris becomes erect and highly sensitive and retracts under its little hood, the upper third of the vagina changes and enlarges, and the vagina produces lubrication. These things might be what you are feeling.
When all these changes reach a certain level, an orgasm happens. An orgasm is a release of all this tension and usually goes along with a very pleasurable sensation. Sometimes this sensation is just felt in the genitals but often it is felt all over, and for some people begins in their toes then travels up their body. With an orgasm is a contraction of the muscles in the pelvis and around the base of the penis in guys and a contraction of the pelvic muscles in girls. Muscles go into spasm all over the body for both sexes. There are certain hormones which are released during orgasm that can make you feel relaxed, sleepy and close to your partner.
Finding out what gives you pleasure and what feels good for you takes time. Make sure you are comfortable and have privacy, and then explore with ways of touching yourself. Many girls find they need to have stimulation of the clitoris to have an orgasm, but touching all the genitals can be pleasurable.
All the best and take care.