Pregnant and having period like cramps after sex and mucus plug like discharge (17w)

So i am on my second pregnancy and we do have intercourse once in a while like maybe in two weeks or 10 or 9 days . From last 3 times am having pains in my back and on top my pubic bone not hurting type just noticeable .and from this last two times am having little bit solid jelly like discharge to me that looks to me abit of mucous plug experienced it from my first .

And one more thing i was having same pains and same losing bit of mucus plug in my 1 pregnancy but i was much further along like 34 weeks and now i am just 17 weeks and sex put me in labour last time . I asked doc about it she is saying its normal to have these cramps some women has it .

But now am so scared what if god forbids it put me in labour . So what you guyz recommend i should completely refrain my self from sex or what my mind is blowing .

Dh has a lot of drive and hes concerned about me because am not really comfortable with a sex at this stage but i dont want him feeling like i dont care about his feelings . Am sure he understands this but its just me feeling this way . I dont know what to do .