I’ve taken two test this month both negative!

So at the beginning of the month when I was supposed to get my period it came a day late and was only 3 days and light unlike my usual 7 days I’ve been having since I’ve had my daughter 3 years ago. I’m on birth control but have started to forget to take it in the morning so I take it as soon as i get home. But when my period was late an short I started to get worried and asked my husband to buy test so I could see, (we’re not trying, but no using anything to prevent it besides BC) I took one as soon as he got home and no it was negative. I waited until that weekend to take another one in the morning to see if anything was different still a negative. I’ve been extremely tired, nauseous, moody and have been having pelvic pains. Today I had some spotting and my period not supposed to start until tomorrow. I’m just really confused on why I have all these pregnant symptoms but keep getting negative test results😕