Not sure what to think of it

So I’m 4 months PP I got my period back at exactly 7 weeks PP. So I went to the eye doctor for a paid study to take eye drops for dry eyes. But before I was able to start the study I had to take a pregnancy test because they wanted to make sure I wasn’t pregnant because the eye drops are basically drugs. So I took it it was negative about 2-3 weeks later maybe like 2 days before I was supposed to get my period I felt just a tiny bit nauseous eating that day but I just thought it was the food but I was also thinking maybe I’m pregnant. So I waited to get my period it never came and I’m pretty consistent when it comes to my period but idk I just had a feeling so I went to the store bought a 3 pack and sure enough bright pink lines. I’m pregnant again! I did cry because I feel like I’m not ready or I could be but my son he’s very needy always wants attention always cries because he wants to be held and I just cried because I thought of my son first. My plan was to get pregnant again till next year but I guess the plan came a year early. Do t get me wrong I’m really happy but then I started doing calculations and apparently my baby’s due date is my son’s birthday and of course I got sad again because I wanted my son to have his own month all to himself lol but anywho my bf was shocked like really shocked I barely found out last week Wednesday and he’s still asking me are you sure your pregnant🤣🤦🏻‍♀️ he’s happy just scared for the same reason because our son is a cry baby lol #teamnosleep but he made me go buy a pregnancy test again so I went and got the first response 2 pack I took it I think it was Friday and it was very bright pink both lines but I had an extra test and took that one this morning but the line wasn’t bright like the other one so now I kinda got worried and doctor said I can’t go until I’m 8 weeks which is in 2 weeks so idk what to think. Has this ever happened to anyone?!?!?!?