The clotting is completely normal....It is just part of your lining the womb forms during your cycle to prepare for a fertile egg! And the brown slimy gunge is a mucus formed by your cervix. Nothing to worry about! Its what keeps your cervix closed during pregnancy. The cramps are normal too, its the muscles spasaming I often get it.
I was pregnant last year and miscarried at 4 months I got about 10 times the amount of clots and slimy stuff than normal. If it didnt all come out then you wud just be full of mucus. The spasms happen every month to push it all out, they are sometimes more noticable than others.
If blood clots come out a deep red they are fresh...Blood that is a few days old is often brown or black!
Also not wanting to upset anybody but you can concieve without knowing and for many reasons miscarry having a period that is heavier than normal that may be why u noticed the cramps. It is very common. It happens to every woman without them even knowing!
But dont let that put you off trying!!!! I tried with my ex for 1 1/2 years...We stopped trying and I stopped thinking about getting pregnant next thing I knew I was 2 months pregnant without knowing!! You could try that? Worked for me!! The mind is a powerful thing!!