Pos then neg help please

Natalie
Yesterday i got a vvvfl on a test so tonight iv done another (different brand) asdas own 2 for £1 brand and got a negative result. Has anyone else had this. Im not sure when in period is due because I had my implant removed on the 12th may then had a bleed on the 14th 15th and 16th. Nothing since. So im not sure if i am or not now.... 🤔