A little nervous!

April 11th I got my implanon taken out and my husband and I decided to start trying for baby #2. I usually have a normal 6 day period but have only had a heavy period for  2 days this month and have been feeling nauseous the last 3 mornings and lower back pain the last few weeks.  I took a test that came back negative at the end of last month which came back negative. Has anyone experienced anything like this? Any help is appreciated!