Could I be pregnant??

Chelsea
So this is my first time posting anything and I could really use some feedback. My husband and I have been trying to conceive for about 6 months (I know that's not very long) and I had always been regular every 28 days for 5 days, until I had a very early miscarriage back in August. In didn't even know I was pregnant but since then my periods have been different. I will spot very lightly for 4 days then I will have a very heavy flow for about a week. Today I am 4 days late, 3 negative pregnancy tests but I have been having very bad heartburn for about a week which a friend said could be a early sign. There is no spotting or bleeding at all, I haven't been on BC in over 2 years. My breasts are sore and I have some cramping. I'm having cravings for Italian food (although I don't think that means much lol.). I just want to know if I could be pregnant. If anyone else has had this problem or if my period is just running late. HELP!!