Please help! I'm sooo frustrated and confused??

Okay so I had a miscarriage and a D&C; on February 10 and I've had on and off spotting for the last 4 weeks. The last time I got my hcg tested was just over 2 weeks ago and my hcg was down to a 50... My husband and I were together for the first time this past Monday night and three days later I was spotting again...anyways I took a hpt and it was positive but I know that you can't get a positive after 5 days of having sex it takes almost 2 weeks...so I'm assuming it's leftover hcg from my mis carriage but I took another test today and I might be crazy but it almost seems darker?? I'm not sure wants going on I'm going to call my doctors in the morning but would love your thoughts!!! Am I loosing it?? Is the line darker??