Implantation Symptoms or not? Don't want another BFN :(

I am currently 8dpo. It's all been going well until yesterday at 7dpo I got back pain (almost like ache flutters that come and go. Nothing painful really) and cramps off and on half of the day. Then it was over. At 6-7dpo I was super gassy. But today it's like all of this is over.

I've got no cramps or backache today. Not really gassy. Not any other symptoms. Do you think this was implantation or not? I ovulate early do my period isn't due for another 10 days.

If it's implantation....is it possible to have symptoms one day and then gone the next? I don't want to get excited just to see another BFN. Two years now