Ya I had suspicions but didn't know for sure until I took a test. And I didn't buy the fancy ones just dollar store ones :)
When i got positive. And then if ur still not sure then wait for the big signs like nauseous.
Aside from missing your period and doing. A.test you may have some other symptoms such as sore breasts, sore back, nausea, morning sickness, headaches, fatigue.