Antabiotics and birth control

Okay please be patient with me and kind. I know many people arent the most supportive on this app but please fallow me through this.

So I've been on the nexplanon birthcontrol for about 1 year and 8 months. The first full year I had the random spotting off and on but then it stopped and my periods went almost completely normal. The spotting that I had was the dark brownish red color. Like the color towards the end of a period.

So about two weeks ago I had my period which lasted about a week and then I got uti right after my period. I went to the doctors and got antibiotics which I was on for about 6 days. I took my last does yesterday. While I was taking the antibiotics I had sex a couple times with my husband.

So I woke up in the middle of the night last night last night to go the the bathroom and I was bleeding like I was on my period. It was a bright red color and a fair amount. So far today I keep bleeding but not super heavy but its bright red.

So a while ago I heard something that antibiotics affect birthcontrol and weaken it but as I'm doing research it says there are only two types that do that and it's not what I've been taking. But idk to trust the internet.

Anyways I just want to know if anyone has gone through something similar. If anyone can connect some peaces. I just dont like it when I cant understand my body. I feel like something is off because this is so odd for me.