I had intercourse on 14 sep & on 15sep is my ovulation day... on 15 I feel egg white watery cervical mucus with a tinge of blood in it... is it mean egg has fertilised?

FAR to early to tell anything.
You need to wait for your next missed period.

First, no one can pinpoint to the day, when they ovulate, its just not possible. Second, the first physical manifestation of pregnancy is when you miss a period. So, as noted, it is far too early to tell. You need to wait at least a week, preferably two after your next due date. If you haven't gotten your period by then, you can start taking tests.

How exactly do you know you ovulate on the 15th... Apps are worthless... and unless you keep a Basal temp chart.. or had actual testing to determine when in the cycle their ovulation USUALLY occurs ... few women actually do know because that's something that does not happen at the same point in every woman. And can be inconsistent from month to month in any individual woman.

The egg is microscopic... you can not feel it.

The discharge is probably from ovulation. It is common for women to experience a discharge with a very slight tinge of blood when an egg is released. Usually it is very easy to miss the blood because it is so light. Some women will also experience a little pain like a popping sensation or a bit of cramping.

As has been said it is too early to know if conception is occurring. Note that I am using present tense. This is because the process of conception actually takes a few days.

It generally takes a couple of days for sperm to travel to the fallopian tubes. They can survive for up to a week depending on several conditions waiting for an egg to be released. Eggs, on the other hand, once released last for about 24 hours. If a sperm does fertilize the egg, it then takes a couple of days for the fertilized egg to make its way to the uterus. Then if conditions are right it implants on the wall of the uterus. Hopefully beginning a healthy pregnancy.

As you can see, you would still be in the very early stage when conception may or may not be happening.

It is generally best to wait until you miss a period to test. Waiting gives time for your body to produce enough hormones to give a more accurate reading on the test. While waiting and if you are actively attempting to conceive, take care of yourself by making any changes you need to for a healthy pregnancy and baby.