Am i pregnant or not?

was 9 days late this month. I finally came on and it lasted for 2 days and then completely disappeared.I also spotted a brown discharge for a day or shall i say a half of day. My cycle normally last for 4 to 5 days. And it arrives every 28 days like clockwork. Prior to that and even now i am tired all of the time, are sore sometimes, i gained 3 pounds and have had morning sickness. Could i be pregnant? i know that sometimes you can have symptoms and end up not being pregnant. Has anyone experienced this before? I took a pregnancy test before my two day cycle and it was negative....