Cramping- negative pregnancy test

So last night and from this morning I have been having a lot of cramping on my lower back. Last night I was also really bloated even though I had barely eaten anything on that day. I don’t ever get my period without pills (pcos) so I highly doubt its period cramps, and also because I have been having unprotected sex since I got off the pill few months ago.

I took a pregnancy test (strip ones) and it was negative even though yesterday afternoon there was a faint line. I don’t know what to think any more. I’m just spending more and more money on more expensive tests like digital and FR just to get a negative.. even though i wait a few days in between!🙄