Positive on first response, negative clearblue?

Has this happened to anyone else? Yesterday morning I got a faint line on a first response so I tested later in the afternoon again with FRER after a 2 hr hold and got a stronger than before light positive within the time frame given, so i wanted to test again this morning to be sure before making an appointment but my local store didn't have anything but the clearblue and cheap test and they were negative... AF is due in 5 days, but I've been nauseous, starving and had the worst sore boobs like with my first pregnancy, it's why I tested early. is first response really that sensitive that it's catching it before the others?

Also I found out very early with my daughter, between 3-4 weeks.