Thank you for posting your question. I will do my best to help you.
Usually, ovulation occurs on 14th day of the cycle and menstruation
on 28th-30th day of cycle ( one is likely to conceive if Intercourse happens anywhere during 12 to 14 days of the menstrual cycle).
First day of the cycle is to be calculated from the day 1 on your period (day 1 will be day one of the cycle)
In your case, as last period date is not mentioned here in query history (request to calculate as when the January 18 will fall in your cycle)
Dont be alarmed, There are home tests for pregnancy
-preg card test kits available over the counters which you can take as early as in 10 days after conception. Please purchase a pregnancy kit and test.
If its negative you can test again after 2- 3 days & reconfirm .
If unsatisfied, kindly consult a gynecologist for further evaluation &advise.