Hi doctor, i am uae resident. And i got married on...

what is the exact starting date of pregnancy in this case ?
Actually , You can't detect the accurate and exact pregnancy date but you can predect the period that pregnancy started at . which always calculated by drs and proffessions by the date of the last menstrual period , In your case it's 18-May 
What is the gestation age in your condition ?
Gestation age is = 7weeks and 4 days 
what is the expected labor day ?
 you labor may start on 25-Feb
What are the sign and symptoms of Pregnancy ?
There are many signs and symptoms which can increase your suspicion of pregnancy , and these include :

1. Delayed period .
2. Nausea and vomiting .
3. Abdominal and low back pain .
4. Breast pain .
5. Changes in appetite .
6. Positive pregnancy tests .

Advice :
you have to follow your dr's instructions