not sure really what to think

ok so on september 21st took a dollar store test and was completely negative, my cycles are so wonky it's unreal. Then on september 28th I had some slight bleeding and then nothing. On 10/2 I took an .88 cent pg test and it came back with the lightest positive, went the next day to get some first response tests the 3 pack took a test on the 3rd came up a better positive than the cheap one. I repeated tests every 2 days to watch line progression. On 10/12 went in for a doctors appointment thinking I'd be around 8 weeks pregnant from my last period on 8/14, and they did a pap, well after the pap I went home and started to have mild cramping, and then about 2 a.m Saturday morning started spotting rusty /dark colored blood. went and layed down woke up and it had stopped. Sunday I spotted some as well which also looked the rusty red/old blood color. also I spotted on Monday 10/15 called the doctor to let them know and they said it was normal after a pap as long as I don't pass any clots or have severe cramping which I didn't. I had an ultrasound scheduled for yesterday 10/16 very light bleeding in the morning, hoping I would be able to see baby and a heartbeat just to be told by sono tech that there was nothing there. he called my doctor and she told me not to freak out that maybe I'm just super early and then ordered lab. I go back 10/19 to find out where my hcg levels are and if I'm still pregnant or I'm going to miscarry. I'm so confused if in fact I am still pregnant I'd be 4 weeks since ovulation/conception if I ovulated on 9/16 like I think I did possibly. I'm sorry this is super long I'm just so confused trying to stay hopeful but at the same time feel like I should just brace myself for a full on miscarriage would be the 2nd in 2 years. my first was in January 2016.