Could i be pregnant or is it just in my head....?

okay liston up Lady's....i don't really have anyone els to talk to so why not ask on here.... so this is whats going on......... i have never been pregnant a day in my life...(been having since i was 13 unprotected) . ....i have had a feoncee for almost a year now i am 18 and trying o so hard for a kid.... i have wanted on ever since i new about baby's...... (my periods are like .i usually have Very heavy flo and lots of cramps at the beginning of it and it last 5-7 days) well last month (january) it was no cramping just a lil maybe when i woke up in the morning..my period was lighter than ever and it came and left and came back?????? can someone tell me whats going on could i be or what!!!!!!!!!!!!!!!!!!!!!!!!!!?????!!!!!…