Need some opinions please

I started a new depression med a month ago, and my period has been weird since. There's no way it would have a direct effect on it though, per my dr. I spotted on Wednesday and Thursday of last week but nothing else since February and nothing since. I've taken 2 pregnancy tests and they've both been negative, but my nipples and breasts have been sore and my cat has been very attentive (they can sometimes sense pregnancy). How likely is it that the two tests were false negatives?