Im really bad at running any exercises i can do to improve my fitness?

when i run i find myself getting alot of cramps n hard to breathe and stuff im really unfit but im not like fat or anything. im just.. weak i guess.

any healthy ways to quickly improve my fitness?

You can't really improve fitness quickly. You can put in the time and effort and build your strength over a period of time.

Practice jogging. Move at a pace faster then a walk, but not a run. When you get crampy and you can't breathe, keep working and try to go as long as possible. If you have to stop, keep walking. Walk fast and get your breath back. Then kick it up to a jog again. Put in 30-40 minutes three times a week. In a month, you'll be much better.

Alternate running and walking, gradually (over several weeks) increase the percent of time spent running vs. walking.

Swimming and cycling are nearly as good as running for building endurance.

Walk. Swim. Yoga. Bike.

Aerobics usually does the trick.. Also things such as climbing stairs, step ups or star jumps.

Do aerobics. Then running will be no problem for you anymore.