I don't want to waste my money on a digital test if I'm not pregnant someone HELP PLZ

Ok so I'm about to actually go to the store for a digital test because I only had a 2 day period and it started early Also and it was so different I didn't really cramp either but I had soar breast for 2 weeks extremely so so soar breast but my period didn't even last that long and started 2 days early should I get a digital or is this just a weird period ? Because I never had a period start early and last only 2 days im usually always on time and last 5 to 6 days 
Also a digital tells you how much weeks your pregnant so I want that just incase 
Another reason is because I tested early twice and got a negative so wanted a digital This time