Confused

I haven’t gotten my period this month. I have this app to help me track it and according to it im 6 days late. I know sometimes periods are irregular but I’ve never had it around after the 15th. I’ve been noticing slight to sharp pain in my breast. Kinda feels like someone is squishing them in a fist from the inside. The last couple days I haven’t been able to lay on my stomach without hurting after 2-5 mins. I know i should just go take a test but now a days they’re getting expensive for just 2 and sometimes they don’t work right. Any suggestions/ opinions?