Need help!!

So for the past 3 or so weeks I have had nausea, headaches, fatigue and have been lightheaded. I took 2 pregnancy tests about 4 or 5 days ago that were different brands and they both came out positive. I took a few more tests for the next 3 days and they came out negative and then four days ago I started bleeding but it was spotting and (tmi) it was light brown and then yesterday ended up a darker brown. I also was dizzy two days ago, the whole room was spinning and I was very unsteady and nauseous at the same time and I am still getting nauseous throughout the day. I do have an appointment for a pregnancy test on the 30th but I am just very confused because I don’t know what any of this means. If any one has had this happened or knows what might be going on please let me know! Thank you