Is my period too light?

I have noticed since TTC it seems my periods are getting lighter and lighter. Especially this one. Started with lint spotting used one panty liner the first day. Second day little heavier used one tampon. Probably could have used two but was at work and forgot to bring an extra so i used one that was completely full but switched to a liner after which was not full by the next morning. So day 3 i used only a panty liner as well but it was just like brown blood and didnt even fill up one whole panty liner the entire day even u til this morning. Now im not using anything and have only little ameara of blood when i wipe. Im afraid my periods are too light for me to get pregnant. There must be some underlying issue. Or so you guys think I could be pregnant and thats why it was so light? Mind you my periods are usually quite light but not this light... Any advice is great.