negative test, period & pregnancy symptoms

Jennifer
Hi my name is Jennifer (26) and I broke up with my ex 4 weeks ago. The last time that we had sex was about 7 weeks ago (we always use condom). The last week of December I took a pregnancy test, because I have been feeling weird (sored breast, cold symptoms, tiredness)The test results was negative and I also got my period that day, so that was for me a double confirmation. I have been having my period normal, only this month it took longer, something that never happened before. For the past 2 weeks I have been having headaches every day, in the morning when I wake up and in the afternoon with nausea. I'm very skinny (59 kg) even though I eat a lot, but since then I gained 4 kg, and the funny thing is that I've lost my appetite. I'm not eating like I used to, because I've been having food aversions. Other symptoms include lower back pain, pimples, tingling sensation in the breasts, hot flashes, gassy (specially while sleeping), I have been pooping more, strong sense of smell, strong urine smell, excessive vaginal discharge, and my allergies are driving me crazy! I remember one time we had sex I bled a little, that was in the beginning of January, few days after my period. The last time that we had sex I was so wet that it just dripped. Once I had a sharp very painful off and on stinging feeling on the left side of my stomach. It felt like gas, but it was different, more painful. I could hardly walk. This pain stopped after 2 days. 
My ex and I dated for 3 months, and I broke up with him after I told him about the pregnancy test that I took. He told me that day that he never wanted children, so that was mainly the reason why I broke up with him. Maybe this sounds stupid, but lately I have been getting like "signals". When I go shopping, kids come to talk/play with me, my facebook and instagram news feed is full of baby/pregnancy articles. My friend who's a mom have been tagging me in baby stuff, and I didn't tell her anything. The other day my aunty entered a maternity shop with me, because everything was on sale and she thought that she could find something for her (she's not pregnant). 
Even though the pregnancy test that I took 2 months ago was negative and I have been having my period, all these symptoms and "signs" are worrying me. I've read that you can have you "period" and still be pregnant. Btw, the test that I bought was a cheap one. Maybe someone can relate to this, before I buy another test?