Unable to conceive trying so much please

I am trying to conceive for 2-3months but could not.this month I was 15 day late I thought I am pregnant as I was having some symptoms also like dizziness pain in my lower abdomen back pain I was even unable to climb 2-3 steps stairs could not even bend to pickup anything it was painful for me also felt very tired could not stand for long just wanted to take rest but due to household work I had to do work. Then after 15 days of late I got periods on 26th of this month. It was very painful I usually don't experience such pain and clots were there whis otherwise doesn't come. Now I think maybe I was pregnant and miscarriage happened. But I am not sure because I didn't take any test. So just wanted to know was there something or it was just late periods. And please help me conceive by giving some advice that I should follow this month to conceive. Thanks