Strange period and cramping

So this app said my period was due Monday and Monday morning I had very thick like egg white cm dark red and brown bleeding. I figured ok here's the start to my wonderful period and got ready for the gym. Well I didn't bleed enough to even fill a panty liner and it had changed to just a weird brown color. The bleeding also didn't even last half the day and it was over. I usually have light periods but this was different. Also Tuesday after the bleeding was gone I started getting cramps on both sides of my lower abdomen and in the middle of my lower abdomen. They aren't persistent but when I do get one it really hurts, so much I've been in the bed all day today and as long as I lay still they don't really happen. Has anyone had this happen to them before? Before anyone has to ask no I am not on any type of birth control and no my husband doesn't pull out or use condoms we both agreed if I could get pregnant after being told I can't we both would be happy so no need to prevent it and we had sex every day during my fertile week.