Cramps & bleeding

Lina
Hi so I'm not sure what's happening...
My period ended two weeks ago (went for about 6 days and it was thick and deep red looked almost black or brown) and I had intercourse one week ago (my partner put on a condom halfway through & long before he finished). 
Last night I experienced some bleeding and this morning I have cramps as well. Could it be implantation bleeding or could this happen sometimes?