Ay anak, I can really feel your worry, and it's so valid given what you've been through. Please follow up with your OB soon, definitely before your next scheduled visit if you're concerned, okay? They know your full history at may access sa ultrasound results mo, so they're best equipped to guide you through this.
A few of us mums have gone through similar scares, and ang dami ng factors talaga, ang UTI, the spotting, the timing, kaya kailangan talaga ng professional eyes on your case. Wag mag-overthink (I know, easier said than done ha!), but trust your doctor and go back if anything changes or if the spotting gets heavier. Fingers crossed for you, mama, sending you all the positive thoughts. Keep us posted!