Failed test?

Help! Don’t know what I should do. My period had been late the last couple of months by 10 days exactly each time. This month it has now been 14 days late. I have taken 2 tests, both came back without a second line. I have been nauseous, having weird cramps that make me think I’m about to get my period then don’t get it, back pains, and I had an emotional breakdown the other day. Also been craving McDonalds and Big Macs because I’ve been having an issue with loosing weight and I wanted to fatten up really quick so thought that would be a good try lol. I’ve only eaten probably 5 in the span of 3 weeks and I’ve gained a chunk of weight that I didn’t have before. Also coming from the girl who eats Chick-fil-A everyday, not sure if it’s from the Big Macs or not 😂 I have one more home test and not sure when to take it to get the most accurate result, or if I should just go in and get a test done. Never been pregnant before or ttc so not sure what to look for or be worried for.